diff --git a/Cargo.lock b/Cargo.lock
index 2bd1a3c..655eb86 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -99,9 +99,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.67"
+version = "0.2.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eb147597cdf94ed43ab7a9038716637d2d1bf2bc571da995d0028dec06bd3018"
+checksum = "dea0c0405123bba743ee3f91f49b1c7cfb684eef0da0a50110f758ccf24cdff0"
 
 [[package]]
 name = "maybe-uninit"
@@ -111,11 +111,11 @@ checksum = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
 
 [[package]]
 name = "memoffset"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "75189eb85871ea5c2e2c15abbdd541185f63b408415e5051f5cac122d8c774b9"
+checksum = "b4fc2c02a7e374099d4ee95a193111f72d2110197fe200272371758f6c3643d8"
 dependencies = [
- "rustc_version",
+ "autocfg",
 ]
 
 [[package]]
@@ -145,6 +145,7 @@ dependencies = [
  "rand_chacha",
  "rand_core",
  "rand_hc",
+ "rand_pcg",
 ]
 
 [[package]]
@@ -175,6 +176,15 @@ dependencies = [
  "rand_core",
 ]
 
+[[package]]
+name = "rand_pcg"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "16abd0c1b639e9eb4d7c50c0b8100b0d0f849be2349829c740fe8e6eb4816429"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "rayon"
 version = "1.3.0"
@@ -208,15 +218,6 @@ dependencies = [
  "sdl2",
 ]
 
-[[package]]
-name = "rustc_version"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
-dependencies = [
- "semver",
-]
-
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -245,21 +246,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "semver"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
-dependencies = [
- "semver-parser",
-]
-
-[[package]]
-name = "semver-parser"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
-
 [[package]]
 name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"
diff --git a/Cargo.toml b/Cargo.toml
index 9f661c6..8ea7aac 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,7 +4,11 @@ version = "0.1.0"
 authors = ["ishanjain28 <ishanjain28@gmail.com>"]
 edition = "2018"
 
+
+[features]
+gui = ["sdl2"]
+
 [dependencies]
-sdl2 = "0.33.0"
-rand = "0.7.3"
+sdl2 = { version = "0.33.0", optional = true }
+rand = { version = "0.7.3", features = ["small_rng"] }
 rayon = "1.3.0"
diff --git a/src/camera.rs b/src/camera.rs
index bed30fe..8901532 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -8,15 +8,15 @@ pub struct Camera {
     horizontal: Vec3,
     vertical: Vec3,
     lower_left_corner: Vec3,
-    lens_radius: f32,
+    lens_radius: f64,
 
     // position vectors
     u: Vec3,
     v: Vec3,
     w: Vec3,
 
-    shutter_open: f32,
-    shutter_close: f32,
+    shutter_open: f64,
+    shutter_close: f64,
 }
 
 impl Camera {
@@ -29,15 +29,15 @@ impl Camera {
         look_from: Vec3,
         look_at: Vec3,
         v_up: Vec3,
-        vertical_fov: f32,
-        aspect: f32,
-        aperture: f32,
-        focus_distance: f32,
-        shutter_open: f32,
-        shutter_close: f32,
+        vertical_fov: f64,
+        aspect: f64,
+        aperture: f64,
+        focus_distance: f64,
+        shutter_open: f64,
+        shutter_close: f64,
     ) -> Self {
         // convert degree to radian
-        let angle = vertical_fov * std::f32::consts::PI / 180.0;
+        let angle = vertical_fov * std::f64::consts::PI / 180.0;
         let half_height = (angle / 2.0).tan();
         let half_width = aspect * half_height;
 
@@ -68,11 +68,10 @@ impl Camera {
         }
     }
 
-    pub fn get_ray(&self, u: f32, v: f32) -> Ray {
-        let mut rng = rand::thread_rng();
-        let rd = random_in_unit_disk(&mut rng) * self.lens_radius;
+    pub fn get_ray<R: Rng + ?Sized>(&self, u: f64, v: f64, rng: &mut R) -> Ray {
+        let rd = random_in_unit_disk(rng) * self.lens_radius;
         let offset = self.u * rd.x() + self.v * rd.y();
-        let time = self.shutter_open + rng.gen::<f32>() * (self.shutter_close - self.shutter_open);
+        let time = self.shutter_open + rng.gen::<f64>() * (self.shutter_close - self.shutter_open);
         Ray::new(
             self.origin + offset,
             self.lower_left_corner + self.horizontal * u + self.vertical * v - self.origin - offset,
@@ -81,11 +80,11 @@ impl Camera {
     }
 }
 
-fn random_in_unit_disk(rng: &mut rand::rngs::ThreadRng) -> Vec3 {
-    let mut p = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), 0.0) * 2.0 - Vec3::new(1.0, 1.0, 0.0);
+fn random_in_unit_disk<R: Rng + ?Sized>(rng: &mut R) -> Vec3 {
+    let mut p = Vec3::new(rng.gen::<f64>(), rng.gen::<f64>(), 0.0) * 2.0 - Vec3::new(1.0, 1.0, 0.0);
 
     while p.dot(&p) >= 1.0 {
-        p = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), 0.0) * 2.0 - Vec3::new(1.0, 0.0, 0.0);
+        p = Vec3::new(rng.gen::<f64>(), rng.gen::<f64>(), 0.0) * 2.0 - Vec3::new(1.0, 0.0, 0.0);
     }
     p
 }
diff --git a/src/demo.rs b/src/demo.rs
new file mode 100644
index 0000000..3ae7db7
--- /dev/null
+++ b/src/demo.rs
@@ -0,0 +1,290 @@
+use {
+    crate::{
+        types::{
+            material::{Dielectric, Lambertian, Metal},
+            Hitable, HitableList, MovingSphere, Ray, Sphere, Vec3,
+        },
+        Camera, HORIZONTAL_PARTITION, VERTICAL_PARTITION,
+    },
+    rand::{rngs::SmallRng, Rng, SeedableRng},
+    rayon::prelude::*,
+    std::{
+        fmt::{Display, Formatter, Result as FmtResult},
+        fs::File,
+        io::Write,
+        sync::{Arc, Mutex},
+    },
+};
+
+#[derive(Debug)]
+pub struct Chunk {
+    num: usize,
+    x: usize,
+    y: usize,
+    nx: usize,
+    ny: usize,
+    start_x: usize,
+    start_y: usize,
+    buffer: Vec<u8>,
+}
+
+impl Display for Chunk {
+    fn fmt(&self, f: &mut Formatter) -> FmtResult {
+        write!(
+            f,
+            "Chunk #{}: Start X = {} Start Y = {} Size X = {} Size = {}",
+            self.num, self.start_x, self.start_y, self.nx, self.ny
+        )
+    }
+}
+
+pub struct Demo;
+
+impl Demo {
+    pub fn name(&self) -> &'static str {
+        "motion_blur"
+    }
+
+    fn world(&self) -> HitableList {
+        let mut world = HitableList {
+            list: Vec::with_capacity(500),
+        };
+
+        let mut rng = rand::thread_rng();
+        let mut rng = SmallRng::from_rng(&mut rng).unwrap();
+
+        world.push(Box::new(Sphere::new(
+            Vec3::new(0.0, -1000.0, 0.0),
+            1000.0,
+            Lambertian::new(Vec3::new(0.5, 0.5, 0.5)),
+        )));
+
+        let radius = 0.2;
+        let l = Vec3::new(4.0, 0.2, 0.0);
+
+        for a in -10..10 {
+            let a = a as f64;
+            for b in -10..10 {
+                let b = b as f64;
+                let choose_material_probability = rng.gen::<f64>();
+                let center = Vec3::new(a + 0.9 * rng.gen::<f64>(), 0.2, b + 0.9 * rng.gen::<f64>());
+
+                if (center - l).length() > 0.9 {
+                    if choose_material_probability < 0.8 {
+                        // diffuse material
+                        world.push(Box::new(MovingSphere::new(
+                            center,
+                            center + Vec3::new(0.0, 0.5 * rng.gen::<f64>(), 0.0),
+                            0.0,
+                            1.0,
+                            radius,
+                            Lambertian::new(Vec3::new(
+                                rng.gen::<f64>() * rng.gen::<f64>(),
+                                rng.gen::<f64>() * rng.gen::<f64>(),
+                                rng.gen::<f64>() * rng.gen::<f64>(),
+                            )),
+                        )));
+                    } else if choose_material_probability < 0.95 {
+                        // metal material
+                        world.push(Box::new(Sphere::new(
+                            center,
+                            radius,
+                            Metal::with_fuzz(
+                                Vec3::new(
+                                    (1.0 + rng.gen::<f64>()) * 0.5,
+                                    (1.0 + rng.gen::<f64>()) * 0.5,
+                                    (1.0 + rng.gen::<f64>()) * 0.5,
+                                ),
+                                0.5 * rng.gen::<f64>(),
+                            ),
+                        )));
+                    } else {
+                        // glass material
+                        world.push(Box::new(Sphere::new(center, radius, Dielectric::new(1.5))));
+                    }
+                }
+            }
+        }
+
+        world.push(Box::new(Sphere::new(
+            Vec3::new(0.0, 1.0, 0.0),
+            1.0,
+            Dielectric::new(1.5),
+        )));
+        world.push(Box::new(Sphere::new(
+            Vec3::new(-4.0, 1.0, 0.0),
+            1.0,
+            Lambertian::new(Vec3::new(0.4, 0.2, 0.1)),
+        )));
+        world.push(Box::new(Sphere::new(
+            Vec3::new(4.0, 1.0, 0.0),
+            1.0,
+            Metal::with_fuzz(Vec3::new(0.7, 0.6, 0.5), 0.0),
+        )));
+
+        world
+    }
+
+    fn camera(&self, aspect_ratio: f64) -> Camera {
+        let lookfrom = Vec3::new(13.0, 2.0, 3.0);
+        let lookat = Vec3::new(0.0, 0.0, 0.0);
+        let aperture = 0.1;
+        let focus_distance = 10.0;
+        Camera::new(
+            lookfrom,
+            lookat,
+            Vec3::new(0.0, 1.0, 0.0),
+            20.0,
+            aspect_ratio,
+            aperture,
+            focus_distance,
+            0.0,
+            1.0,
+        )
+    }
+
+    fn render_chunk(&self, chunk: &mut Chunk, camera: &Camera, world: &HitableList, samples: u8) {
+        let &mut Chunk {
+            num: _,
+            x,
+            y,
+            nx,
+            ny,
+            start_x,
+            start_y,
+            ref mut buffer,
+        } = chunk;
+        let mut offset = 0;
+        let mut rng = rand::thread_rng();
+        let mut rng = SmallRng::from_rng(&mut rng).unwrap();
+
+        assert!(buffer.len() >= nx * ny * 4);
+
+        (start_y..start_y + ny).for_each(|j| {
+            (start_x..start_x + nx).for_each(|i| {
+                let mut color = Vec3::new(0.0, 0.0, 0.0);
+                for _s in 0..samples {
+                    let u = (i as f64 + rng.gen::<f64>()) / x as f64;
+                    let v = (j as f64 + rng.gen::<f64>()) / y as f64;
+
+                    let ray = camera.get_ray(u, v, &mut rng);
+                    color += calc_color(ray, &world, 0, &mut rng);
+                }
+
+                color /= samples as f64;
+                self.update_rgb(buffer, color, offset);
+                offset += 4;
+            });
+        });
+    }
+
+    pub fn render(&self, buf: &mut Vec<u8>, x: usize, y: usize, samples: u8) {
+        let world = self.world();
+        let delta_x = x / VERTICAL_PARTITION;
+        let delta_y = y / HORIZONTAL_PARTITION;
+        let remx = x % VERTICAL_PARTITION;
+        let remy = y % HORIZONTAL_PARTITION;
+
+        // There can be tiny error here if the canvas height/width is not perfectly divisible
+        // by vertical/horizontal partitions in the chunks around the edges
+        // but umm, i'll just ignore those for now.
+        let camera = self.camera(delta_x as f64 / delta_y as f64);
+        let buf = Arc::new(Mutex::new(buf));
+
+        (0..VERTICAL_PARTITION).into_par_iter().for_each(|j| {
+            let buf = buf.clone();
+            (0..HORIZONTAL_PARTITION).into_par_iter().for_each(|i| {
+                let mut nx = delta_x;
+                let mut ny = delta_y;
+                let start_y = j * ny;
+                let start_x = i * nx;
+
+                match (i + 1, j + 1) {
+                    (HORIZONTAL_PARTITION, VERTICAL_PARTITION) => {
+                        nx += remx;
+                        ny += remy;
+                    }
+                    (HORIZONTAL_PARTITION, _) => nx += remx,
+                    (_, VERTICAL_PARTITION) => ny += remy,
+                    _ => (),
+                };
+
+                let mut chunk = Chunk {
+                    num: j * HORIZONTAL_PARTITION + i,
+                    x,
+                    y,
+                    nx,
+                    ny,
+                    start_x,
+                    start_y,
+                    buffer: vec![0; nx * ny * 4],
+                };
+
+                println!("{}", chunk);
+                self.render_chunk(&mut chunk, &camera, &world, samples);
+
+                let mut buf = buf.lock().unwrap();
+                let mut temp_offset = 0;
+                for j in start_y..start_y + ny {
+                    let real_offset = ((y - j - 1) * x + start_x) * 4;
+
+                    buf[real_offset..real_offset + nx * 4]
+                        .copy_from_slice(&chunk.buffer[temp_offset..temp_offset + nx * 4]);
+
+                    temp_offset += nx * 4;
+                }
+                println!("Rendered {}", chunk);
+            });
+        });
+    }
+
+    #[inline]
+    fn update_rgb(&self, buffer: &mut [u8], color: Vec3, offset: usize) {
+        if let Some(pos) = buffer.get_mut(offset) {
+            *pos = (255.99 * color.r().sqrt()) as u8;
+        }
+        if let Some(pos) = buffer.get_mut(offset + 1) {
+            *pos = (255.99 * color.g().sqrt()) as u8;
+        }
+        if let Some(pos) = buffer.get_mut(offset + 2) {
+            *pos = (255.99 * color.b().sqrt()) as u8;
+        }
+    }
+
+    pub fn save_as_ppm(&self, buf: &[u8], width: usize, height: usize) {
+        let header = format!("P3\n{} {}\n255\n", width, height);
+
+        let mut file = match File::create(&format!("{}-{}x{}.ppm", self.name(), width, height)) {
+            Ok(file) => file,
+            Err(e) => panic!("couldn't create {}: {}", self.name(), e),
+        };
+        file.write_all(header.as_bytes())
+            .expect("error in writing file header");
+
+        for i in buf.chunks(4) {
+            match file.write_all(format!("{} {} {}\n", i[0], i[1], i[2]).as_bytes()) {
+                Ok(_) => (),
+                Err(e) => panic!("couldn't write to {}: {}", self.name(), e),
+            }
+        }
+    }
+}
+
+fn calc_color(ray: Ray, world: &HitableList, depth: u32, rng: &mut SmallRng) -> Vec3 {
+    if let Some(hit_rec) = world.hit(&ray, 0.001, std::f64::MAX) {
+        if depth >= 50 {
+            Vec3::new(0.0, 0.0, 0.0)
+        } else {
+            let material = hit_rec.material;
+            if let (attenuation, Some(scattered_ray)) = material.scatter(&ray, &hit_rec, rng) {
+                calc_color(scattered_ray, &world, depth + 1, rng) * attenuation
+            } else {
+                Vec3::new(0.0, 0.0, 0.0)
+            }
+        }
+    } else {
+        let unit_direction = ray.direction().unit_vector();
+        let t = 0.5 * (unit_direction.y() + 1.0);
+        Vec3::new(1.0, 1.0, 1.0) * (1.0 - t) + Vec3::new(0.5, 0.7, 1.0) * t
+    }
+}
diff --git a/src/demos/mod.rs b/src/demos/mod.rs
deleted file mode 100644
index 6caa751..0000000
--- a/src/demos/mod.rs
+++ /dev/null
@@ -1,117 +0,0 @@
-use {
-    crate::{
-        types::{HitableList, Vec3},
-        Camera, HORIZONTAL_PARTITION, VERTICAL_PARTITION,
-    },
-    rayon::prelude::*,
-    std::{
-        fs::File,
-        io::Write,
-        sync::{Arc, Mutex},
-    },
-};
-
-mod motion_blur;
-
-pub use motion_blur::MotionBlur;
-
-pub struct Chunk {
-    x: usize,
-    y: usize,
-    nx: usize,
-    ny: usize,
-    start_x: usize,
-    start_y: usize,
-    buffer: Vec<u8>,
-}
-
-pub trait Demo: std::marker::Sync {
-    fn render(&self, buf: &mut Vec<u8>, width: usize, height: usize, samples: u8) {
-        let nx = width / VERTICAL_PARTITION;
-        let ny = height / HORIZONTAL_PARTITION;
-        let world = self.world();
-        let camera = self.camera(nx as f32 / ny as f32);
-
-        let buf = Arc::new(Mutex::new(buf));
-
-        (0..VERTICAL_PARTITION).into_par_iter().for_each(|j| {
-            let buf = buf.clone();
-            (0..HORIZONTAL_PARTITION).into_par_iter().for_each(|i| {
-                let start_y = j * ny;
-                let start_x = i * nx;
-                let x = width;
-                let y = height;
-                let mut chunk = Chunk {
-                    x,
-                    y,
-                    nx,
-                    ny,
-                    start_x,
-                    start_y,
-                    buffer: vec![0; nx * ny * 4],
-                };
-                self.render_chunk(&mut chunk, camera.as_ref(), world.as_ref(), samples);
-
-                let mut buf = buf.lock().unwrap();
-
-                let mut temp_offset = 0;
-                for j in start_y..start_y + ny {
-                    let real_offset = ((y - j - 1) * x + start_x) * 4;
-
-                    buf[real_offset..real_offset + nx * 4]
-                        .copy_from_slice(&chunk.buffer[temp_offset..temp_offset + nx * 4]);
-
-                    temp_offset += nx * 4;
-                }
-            })
-        });
-    }
-
-    fn world(&self) -> Option<HitableList> {
-        None
-    }
-
-    fn camera(&self, aspect_ratio: f32) -> Option<Camera> {
-        let lookfrom = Vec3::new(0.0, 0.0, 0.0);
-        let lookat = Vec3::new(0.0, 0.0, -1.0);
-        Some(Camera::new(
-            lookfrom,
-            lookat,
-            Vec3::new(0.0, 1.0, 0.0),
-            90.0,
-            aspect_ratio,
-            0.0, //aperture
-            1.0, // focus_distance
-            0.0, // shutter open time
-            1.0, // shutter close time
-        ))
-    }
-
-    fn render_chunk(
-        &self,
-        chunk: &mut Chunk,
-        camera: Option<&Camera>,
-        world: Option<&HitableList>,
-        samples: u8,
-    );
-
-    fn name(&self) -> &'static str;
-
-    fn save_as_ppm(&self, buf: &[u8], width: usize, height: usize) {
-        let header = format!("P3\n{} {}\n255\n", width, height);
-
-        let mut file = match File::create(&format!("{}-{}x{}.ppm", self.name(), width, height)) {
-            Ok(file) => file,
-            Err(e) => panic!("couldn't create {}: {}", self.name(), e),
-        };
-        file.write_all(header.as_bytes())
-            .expect("error in writing file header");
-
-        for i in buf.chunks(4) {
-            match file.write_all(format!("{} {} {}\n", i[0], i[1], i[2]).as_bytes()) {
-                Ok(_) => (),
-                Err(e) => panic!("couldn't write to {}: {}", self.name(), e),
-            }
-        }
-    }
-}
diff --git a/src/demos/motion_blur.rs b/src/demos/motion_blur.rs
deleted file mode 100644
index 8cf9afa..0000000
--- a/src/demos/motion_blur.rs
+++ /dev/null
@@ -1,185 +0,0 @@
-use {
-    crate::{
-        demos::{Chunk, Demo},
-        types::{
-            material::{Dielectric, Lambertian, Metal},
-            Hitable, HitableList, MovingSphere, Ray, Sphere, Vec3,
-        },
-        Camera,
-    },
-    rand::Rng,
-};
-
-const RANGE: i32 = 10;
-
-pub struct MotionBlur;
-
-impl Demo for MotionBlur {
-    fn name(&self) -> &'static str {
-        "motion_blur"
-    }
-
-    fn world(&self) -> Option<HitableList> {
-        let mut world = HitableList {
-            list: Vec::with_capacity(500),
-        };
-
-        world.push(Box::new(Sphere::new(
-            Vec3::new(0.0, -1000.0, 0.0),
-            1000.0,
-            Box::new(Lambertian::new(Vec3::new(0.5, 0.5, 0.5))),
-        )));
-
-        let mut rng = rand::thread_rng();
-        let radius = 0.2;
-        let l = Vec3::new(4.0, 0.2, 0.0);
-
-        for a in -RANGE..RANGE {
-            let a = a as f32;
-            for b in -RANGE..RANGE {
-                let b = b as f32;
-                let choose_material_probability = rng.gen::<f32>();
-                let center = Vec3::new(a + 0.9 * rng.gen::<f32>(), 0.2, b + 0.9 * rng.gen::<f32>());
-
-                if (center - l).length() > 0.9 {
-                    if choose_material_probability < 0.8 {
-                        // diffuse material
-                        world.push(Box::new(MovingSphere::new(
-                            center,
-                            center + Vec3::new(0.0, 0.5 * rng.gen::<f32>(), 0.0),
-                            0.0,
-                            1.0,
-                            radius,
-                            Box::new(Lambertian::new(Vec3::new(
-                                rng.gen::<f32>() * rng.gen::<f32>(),
-                                rng.gen::<f32>() * rng.gen::<f32>(),
-                                rng.gen::<f32>() * rng.gen::<f32>(),
-                            ))),
-                        )));
-                    } else if choose_material_probability < 0.95 {
-                        // metal material
-                        world.push(Box::new(Sphere::new(
-                            center,
-                            radius,
-                            Box::new(Metal::with_fuzz(
-                                Vec3::new(
-                                    (1.0 + rng.gen::<f32>()) * 0.5,
-                                    (1.0 + rng.gen::<f32>()) * 0.5,
-                                    (1.0 + rng.gen::<f32>()) * 0.5,
-                                ),
-                                0.5 * rng.gen::<f32>(),
-                            )),
-                        )));
-                    } else {
-                        // glass material
-                        world.push(Box::new(Sphere::new(
-                            center,
-                            radius,
-                            Box::new(Dielectric::new(1.5)),
-                        )));
-                    }
-                }
-            }
-        }
-
-        world.push(Box::new(Sphere::new(
-            Vec3::new(0.0, 1.0, 0.0),
-            1.0,
-            Box::new(Dielectric::new(1.5)),
-        )));
-        world.push(Box::new(Sphere::new(
-            Vec3::new(-4.0, 1.0, 0.0),
-            1.0,
-            Box::new(Lambertian::new(Vec3::new(0.4, 0.2, 0.1))),
-        )));
-        world.push(Box::new(Sphere::new(
-            Vec3::new(4.0, 1.0, 0.0),
-            1.0,
-            Box::new(Metal::with_fuzz(Vec3::new(0.7, 0.6, 0.5), 0.0)),
-        )));
-
-        Some(world)
-    }
-
-    fn camera(&self, aspect_ratio: f32) -> Option<Camera> {
-        let lookfrom = Vec3::new(13.0, 2.0, 3.0);
-        let lookat = Vec3::new(0.0, 0.0, 0.0);
-        let aperture = 0.1;
-        let focus_distance = 10.0;
-        let camera = Camera::new(
-            lookfrom,
-            lookat,
-            Vec3::new(0.0, 1.0, 0.0),
-            20.0,
-            aspect_ratio,
-            aperture,
-            focus_distance,
-            0.0,
-            1.0,
-        );
-        Some(camera)
-    }
-
-    fn render_chunk(
-        &self,
-        chunk: &mut Chunk,
-        camera: Option<&Camera>,
-        world: Option<&HitableList>,
-        samples: u8,
-    ) {
-        let &mut Chunk {
-            x,
-            y,
-            nx,
-            ny,
-            start_x,
-            start_y,
-            ref mut buffer,
-        } = chunk;
-        let camera = camera.unwrap();
-        let world = world.unwrap();
-
-        let mut rng = rand::thread_rng();
-        let mut offset = 0;
-
-        for j in start_y..start_y + ny {
-            for i in start_x..start_x + nx {
-                let mut color = Vec3::new(0.0, 0.0, 0.0);
-                for _s in 0..samples {
-                    let u = (i as f32 + rng.gen::<f32>()) / x as f32;
-                    let v = (j as f32 + rng.gen::<f32>()) / y as f32;
-
-                    let ray = camera.get_ray(u, v);
-                    color += calc_color(ray, &world, 0);
-                }
-
-                color /= samples as f32;
-
-                // gamma 2 corrected
-                buffer[offset] = (255.99 * color.r().sqrt()) as u8;
-                buffer[offset + 1] = (255.99 * color.g().sqrt()) as u8;
-                buffer[offset + 2] = (255.99 * color.b().sqrt()) as u8;
-                offset += 4;
-            }
-        }
-    }
-}
-
-fn calc_color(ray: Ray, world: &HitableList, depth: u32) -> Vec3 {
-    if let Some(hit_rec) = world.hit(&ray, 0.001, std::f32::MAX) {
-        if depth >= 50 {
-            Vec3::new(0.0, 0.0, 0.0)
-        } else {
-            let material = hit_rec.material;
-            if let (attenuation, Some(scattered_ray)) = material.scatter(&ray, &hit_rec) {
-                calc_color(scattered_ray, &world, depth + 1) * attenuation
-            } else {
-                Vec3::new(0.0, 0.0, 0.0)
-            }
-        }
-    } else {
-        let unit_direction = ray.direction().unit_vector();
-        let t = 0.5 * (unit_direction.y() + 1.0);
-        Vec3::new(1.0, 1.0, 1.0) * (1.0 - t) + Vec3::new(0.5, 0.7, 1.0) * t
-    }
-}
diff --git a/src/main.rs b/src/main.rs
index d52c90b..b0259b0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,30 +3,33 @@
 extern crate test;
 
 mod camera;
-mod demos;
+mod demo;
 mod types;
 
 pub use camera::Camera;
 
-use {
-    demos::Demo,
-    sdl2::{
-        event::{Event, WindowEvent},
-        keyboard::Keycode,
-        pixels::PixelFormatEnum,
-    },
-    std::time::Instant,
-};
+use std::time::Instant;
 
 const NUM_SAMPLES: u8 = 100;
 const VERTICAL_PARTITION: usize = 8;
 const HORIZONTAL_PARTITION: usize = 8;
+const WIDTH: usize = 800;
+const HEIGHT: usize = 800;
 
 fn main() -> Result<(), String> {
+    run(WIDTH, HEIGHT)
+}
+
+#[cfg(feature = "gui")]
+fn run(mut width: usize, mut height: usize) -> Result<(), String> {
+    use sdl2::{
+        event::{Event, WindowEvent},
+        keyboard::Keycode,
+        pixels::PixelFormatEnum,
+    };
+
     let sdl_ctx = sdl2::init()?;
     let video_subsys = sdl_ctx.video()?;
-    let (mut width, mut height): (usize, usize) = (2000, 1000);
-
     let window = video_subsys
         .window("Ray tracing in a weekend", width as u32, height as u32)
         .position_centered()
@@ -49,15 +52,9 @@ fn main() -> Result<(), String> {
         .create_texture_static(PixelFormatEnum::BGR888, width as u32, height as u32)
         .map_err(|e| e.to_string())?;
 
-    //println!("{:?} {:?} {:?}", texture.query(), texture.color_mod(), texture.alpha_mod());
+    let active_demo = demo::Demo;
 
-    let mut active_demo: &dyn Demo = &demos::MotionBlur;
-    // TODO: Should update when window is unfocus since the project window retains
-    // data from overlapped window
-    // TODO: Maybe consider using condition variable to make loop {} not run at full
-    // speed at all times pinning a core at 100%
     let mut should_update = true;
-
     loop {
         for event in event_pump.poll_iter() {
             match event {
@@ -97,7 +94,7 @@ fn main() -> Result<(), String> {
             println!(
                 "Demo {} Time Taken(s) = {}",
                 active_demo.name(),
-                now.elapsed().as_secs_f32()
+                now.elapsed().as_secs_f64()
             );
 
             texture.update(None, &buffer, width * 4).unwrap();
@@ -107,3 +104,29 @@ fn main() -> Result<(), String> {
         }
     }
 }
+
+#[cfg(not(feature = "gui"))]
+fn run(width: usize, height: usize) -> Result<(), String> {
+    let mut buffer = vec![0; width * height * 4];
+
+    let demo = demo::Demo;
+
+    println!(
+        "Starting {} at {}x{} with {} samples",
+        demo.name(),
+        width,
+        height,
+        NUM_SAMPLES
+    );
+    let now = Instant::now();
+    demo.render(&mut buffer, width, height, NUM_SAMPLES);
+    println!(
+        "Rendered Demo {}. Time Taken(s) = {}",
+        demo.name(),
+        now.elapsed().as_secs_f64()
+    );
+
+    demo.save_as_ppm(&buffer, width, height);
+
+    Ok(())
+}
diff --git a/src/types/mod.rs b/src/types.rs
similarity index 100%
rename from src/types/mod.rs
rename to src/types.rs
diff --git a/src/types/hitable.rs b/src/types/hitable.rs
index 99935a5..c67dd9a 100644
--- a/src/types/hitable.rs
+++ b/src/types/hitable.rs
@@ -1,7 +1,4 @@
-use {
-    crate::types::Vec3,
-    crate::types::{Material, Ray},
-};
+use crate::types::{Material, Ray, Vec3};
 
 pub struct HitRecord<'a> {
     ///  Rays are represented by A + t * B
@@ -11,7 +8,7 @@ pub struct HitRecord<'a> {
     ///  t is the point at which a ray intersected another object.
     ///  As in, If we put this value of t in A + t * B equation, We'll get the exact
     ///  point at which a ray intersects some other object
-    pub t: f32,
+    pub t: f64,
     /// Ray object otherwise is represented by the Source/Destination points
     /// p is what we get when we perform the operation, A + t * B
     /// i.e. A vector from Ray source to the point t
@@ -21,11 +18,11 @@ pub struct HitRecord<'a> {
     pub normal: Vec3,
 
     /// material if any of the surface
-    pub material: &'a Box<dyn Material>,
+    pub material: &'a dyn Material,
 }
 
 pub trait Hitable: Send + Sync {
-    fn hit(&self, _ray: &Ray, _t_min: f32, _t_max: f32) -> Option<HitRecord> {
+    fn hit(&self, _ray: &Ray, _t_min: f64, _t_max: f64) -> Option<HitRecord> {
         None
     }
 }
diff --git a/src/types/hitable_list.rs b/src/types/hitable_list.rs
index cec3490..f2fac57 100644
--- a/src/types/hitable_list.rs
+++ b/src/types/hitable_list.rs
@@ -5,7 +5,7 @@ pub struct HitableList {
 }
 
 impl Hitable for HitableList {
-    fn hit(&self, ray: &Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+    fn hit(&self, ray: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord> {
         let mut closest_so_far = t_max;
         let mut hit_rec: Option<HitRecord> = None;
         for obj in &self.list {
diff --git a/src/types/material.rs b/src/types/material.rs
index 2362bdf..6da58c9 100644
--- a/src/types/material.rs
+++ b/src/types/material.rs
@@ -1,10 +1,10 @@
 use {
     crate::types::{HitRecord, Ray, Vec3},
-    rand::Rng,
+    rand::{rngs::SmallRng, Rng},
 };
 
 pub trait Material: Send + Sync {
-    fn scatter(&self, ray: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>);
+    fn scatter(&self, ray: &Ray, hit_rec: &HitRecord, rng: &mut SmallRng) -> (Vec3, Option<Ray>);
 }
 
 pub struct Lambertian {
@@ -18,9 +18,8 @@ impl Lambertian {
 }
 
 impl Material for Lambertian {
-    fn scatter(&self, ray: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>) {
-        let mut rng = rand::thread_rng();
-        let target = hit_rec.p + hit_rec.normal + random_point_in_unit_sphere(&mut rng);
+    fn scatter(&self, ray: &Ray, hit_rec: &HitRecord, rng: &mut SmallRng) -> (Vec3, Option<Ray>) {
+        let target = hit_rec.p + hit_rec.normal + random_point_in_unit_sphere(rng);
         let scattered_ray = Ray::new(hit_rec.p, target - hit_rec.p, ray.time());
 
         (self.albedo, Some(scattered_ray))
@@ -29,26 +28,29 @@ impl Material for Lambertian {
 
 pub struct Metal {
     albedo: Vec3,
-    fuzz: f32,
+    fuzz: f64,
 }
 
 impl Metal {
     pub fn new(albedo: Vec3) -> Self {
         Self { albedo, fuzz: 0.0 }
     }
-    pub fn with_fuzz(albedo: Vec3, fuzz: f32) -> Self {
+    pub fn with_fuzz(albedo: Vec3, fuzz: f64) -> Self {
         Self { albedo, fuzz }
     }
 }
 
 impl Material for Metal {
-    fn scatter(&self, ray_in: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>) {
-        let mut rng = rand::thread_rng();
-
+    fn scatter(
+        &self,
+        ray_in: &Ray,
+        hit_rec: &HitRecord,
+        rng: &mut SmallRng,
+    ) -> (Vec3, Option<Ray>) {
         let reflected_ray = reflect(ray_in.direction().unit_vector(), hit_rec.normal);
         let scattered_ray = Ray::new(
             hit_rec.p,
-            reflected_ray + random_point_in_unit_sphere(&mut rng) * self.fuzz,
+            reflected_ray + random_point_in_unit_sphere(rng) * self.fuzz,
             ray_in.time(),
         );
 
@@ -61,21 +63,25 @@ impl Material for Metal {
 }
 
 pub struct Dielectric {
-    reflection_index: f32,
+    reflection_index: f64,
 }
 
 impl Dielectric {
-    pub fn new(reflection_index: f32) -> Self {
+    pub fn new(reflection_index: f64) -> Self {
         Self { reflection_index }
     }
 }
 
 impl Material for Dielectric {
-    fn scatter(&self, ray_in: &Ray, hit_rec: &HitRecord) -> (Vec3, Option<Ray>) {
+    fn scatter(
+        &self,
+        ray_in: &Ray,
+        hit_rec: &HitRecord,
+        rng: &mut SmallRng,
+    ) -> (Vec3, Option<Ray>) {
         let reflected_ray = reflect(ray_in.direction(), hit_rec.normal);
         // Glass absorbs nothing! So, Attenuation is always going to be 1.0 for this
         let attenuation = Vec3::new(1.0, 1.0, 1.0);
-        let mut rng = rand::thread_rng();
 
         let (outward_normal, ni_over_nt, cosine) = if ray_in.direction().dot(&hit_rec.normal) > 0.0
         {
@@ -96,7 +102,7 @@ impl Material for Dielectric {
         if let Some(refracted_ray) = refract(ray_in.direction(), outward_normal, ni_over_nt) {
             let reflect_prob = schlick(cosine, self.reflection_index);
 
-            if rng.gen::<f32>() < reflect_prob {
+            if rng.gen::<f64>() < reflect_prob {
                 (
                     attenuation,
                     Some(Ray::new(hit_rec.p, reflected_ray, ray_in.time())),
@@ -118,7 +124,7 @@ impl Material for Dielectric {
 
 // Christophe Schlick's Polynomial approximation to figure out reflectivity as the angle changes
 // See Fresnel Equations, https://en.wikipedia.org/wiki/Fresnel_equations
-fn schlick(cosine: f32, reflection_index: f32) -> f32 {
+fn schlick(cosine: f64, reflection_index: f64) -> f64 {
     let mut r0 = (1.0 - reflection_index) / (1.0 + reflection_index);
     r0 = r0 * r0;
     r0 + (1.0 - r0) * (1.0 - cosine).powf(5.0)
@@ -129,7 +135,7 @@ fn reflect(incident: Vec3, normal: Vec3) -> Vec3 {
 }
 
 // Snell's Law
-fn refract(incident: Vec3, normal: Vec3, ni_over_nt: f32) -> Option<Vec3> {
+fn refract(incident: Vec3, normal: Vec3, ni_over_nt: f64) -> Option<Vec3> {
     let uv = incident.unit_vector();
     let dt = uv.dot(&normal);
     let discriminant = 1.0 - ni_over_nt * ni_over_nt * (1.0 - dt * dt);
@@ -140,11 +146,11 @@ fn refract(incident: Vec3, normal: Vec3, ni_over_nt: f32) -> Option<Vec3> {
     }
 }
 
-fn random_point_in_unit_sphere(rng: &mut rand::rngs::ThreadRng) -> Vec3 {
-    let mut point = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), rng.gen::<f32>()) * 2.0
+fn random_point_in_unit_sphere<R: Rng + ?Sized>(rng: &mut R) -> Vec3 {
+    let mut point = Vec3::new(rng.gen::<f64>(), rng.gen::<f64>(), rng.gen::<f64>()) * 2.0
         - Vec3::new(1.0, 1.0, 1.0);
     while point.sq_len() >= 1.0 {
-        point = Vec3::new(rng.gen::<f32>(), rng.gen::<f32>(), rng.gen::<f32>()) * 2.0
+        point = Vec3::new(rng.gen::<f64>(), rng.gen::<f64>(), rng.gen::<f64>()) * 2.0
             - Vec3::new(1.0, 1.0, 1.0);
     }
     point
diff --git a/src/types/moving_sphere.rs b/src/types/moving_sphere.rs
index 72f2b4f..2791a4e 100644
--- a/src/types/moving_sphere.rs
+++ b/src/types/moving_sphere.rs
@@ -1,22 +1,22 @@
 use crate::types::{HitRecord, Hitable, Material, Ray, Vec3};
 
-pub struct MovingSphere {
-    radius: f32,
+pub struct MovingSphere<T: Material + Sized> {
+    radius: f64,
     center_start: Vec3,
     center_end: Vec3,
-    time_start: f32,
-    time_end: f32,
-    material: Box<dyn Material>,
+    time_start: f64,
+    time_end: f64,
+    material: T,
 }
 
-impl MovingSphere {
+impl<T: Material + Sized> MovingSphere<T> {
     pub fn new(
         center_start: Vec3,
         center_end: Vec3,
-        time_start: f32,
-        time_end: f32,
-        radius: f32,
-        material: Box<dyn Material>,
+        time_start: f64,
+        time_end: f64,
+        radius: f64,
+        material: T,
     ) -> Self {
         Self {
             center_start,
@@ -28,15 +28,15 @@ impl MovingSphere {
         }
     }
 
-    fn center(&self, time: f32) -> Vec3 {
+    fn center(&self, time: f64) -> Vec3 {
         self.center_start
             + (self.center_end - self.center_start)
                 * ((time - self.time_start) / (self.time_end - self.time_start))
     }
 }
 
-impl Hitable for MovingSphere {
-    fn hit(&self, ray: &Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+impl<T: Material + Sized> Hitable for MovingSphere<T> {
+    fn hit(&self, ray: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord> {
         let oc = ray.origin() - self.center(ray.time());
         let a = ray.direction().dot(&ray.direction());
         let b = oc.dot(&ray.direction());
diff --git a/src/types/ray.rs b/src/types/ray.rs
index d776020..c94a2b4 100644
--- a/src/types/ray.rs
+++ b/src/types/ray.rs
@@ -3,11 +3,11 @@ use crate::types::Vec3;
 pub struct Ray {
     a: Vec3,
     b: Vec3,
-    time: f32,
+    time: f64,
 }
 
 impl Ray {
-    pub fn new(a: Vec3, b: Vec3, time: f32) -> Ray {
+    pub fn new(a: Vec3, b: Vec3, time: f64) -> Ray {
         Ray { a, b, time }
     }
     #[inline]
@@ -19,11 +19,11 @@ impl Ray {
         self.b
     }
     #[inline]
-    pub fn point_at_parameter(&self, t: f32) -> Vec3 {
+    pub fn point_at_parameter(&self, t: f64) -> Vec3 {
         self.a + self.b * t
     }
     #[inline]
-    pub const fn time(&self) -> f32 {
+    pub const fn time(&self) -> f64 {
         self.time
     }
 }
diff --git a/src/types/sphere.rs b/src/types/sphere.rs
index e799943..10a6b87 100644
--- a/src/types/sphere.rs
+++ b/src/types/sphere.rs
@@ -1,13 +1,13 @@
 use crate::types::{HitRecord, Hitable, Material, Ray, Vec3};
 
-pub struct Sphere {
+pub struct Sphere<T: Material + Sized> {
     center: Vec3,
-    radius: f32,
-    material: Box<dyn Material>,
+    radius: f64,
+    material: T,
 }
 
-impl Sphere {
-    pub fn new(center: Vec3, radius: f32, material: Box<dyn Material>) -> Self {
+impl<T: Material + Sized> Sphere<T> {
+    pub fn new(center: Vec3, radius: f64, material: T) -> Self {
         Self {
             center,
             radius,
@@ -16,8 +16,8 @@ impl Sphere {
     }
 }
 
-impl Hitable for Sphere {
-    fn hit(&self, ray: &Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
+impl<T: Material + Sized> Hitable for Sphere<T> {
+    fn hit(&self, ray: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord> {
         let oc = ray.origin() - self.center;
         let a = ray.direction().dot(&ray.direction());
         let b = oc.dot(&ray.direction());
diff --git a/src/types/vec3.rs b/src/types/vec3.rs
index 163eba0..12d931e 100644
--- a/src/types/vec3.rs
+++ b/src/types/vec3.rs
@@ -4,50 +4,50 @@ use std::{
 };
 
 #[derive(Copy, Clone)]
-pub struct Vec3([f32; 3]);
+pub struct Vec3([f64; 3]);
 
 impl Vec3 {
     #[inline]
-    pub const fn new(a: f32, b: f32, c: f32) -> Vec3 {
+    pub const fn new(a: f64, b: f64, c: f64) -> Vec3 {
         Vec3([a, b, c])
     }
     #[inline]
-    pub fn x(&self) -> f32 {
+    pub fn x(&self) -> f64 {
         self[0]
     }
     #[inline]
-    pub fn y(&self) -> f32 {
+    pub fn y(&self) -> f64 {
         self[1]
     }
     #[inline]
-    pub fn z(&self) -> f32 {
+    pub fn z(&self) -> f64 {
         self[2]
     }
     #[inline]
-    pub fn r(&self) -> f32 {
+    pub fn r(&self) -> f64 {
         self[0]
     }
     #[inline]
-    pub fn g(&self) -> f32 {
+    pub fn g(&self) -> f64 {
         self[1]
     }
     #[inline]
-    pub fn b(&self) -> f32 {
+    pub fn b(&self) -> f64 {
         self[2]
     }
 
     #[inline]
-    pub fn length(&self) -> f32 {
+    pub fn length(&self) -> f64 {
         self.sq_len().sqrt()
     }
 
     #[inline]
-    pub fn sq_len(&self) -> f32 {
+    pub fn sq_len(&self) -> f64 {
         self[0] * self[0] + self[1] * self[1] + self[2] * self[2]
     }
 
     #[inline]
-    pub fn dot(&self, v: &Vec3) -> f32 {
+    pub fn dot(&self, v: &Vec3) -> f64 {
         self[0] * v[0] + self[1] * v[1] + self[2] * v[2]
     }
 
@@ -62,7 +62,7 @@ impl Vec3 {
 
     #[inline]
     pub fn make_unit_vector(&mut self) {
-        let k = 1.0f32 / (self[0] * self[0] + self[1] * self[1] + self[2] * self[2]);
+        let k = 1.0f64 / (self[0] * self[0] + self[1] * self[1] + self[2] * self[2]);
         self[0] *= k;
         self[1] *= k;
         self[2] *= k;
@@ -123,17 +123,17 @@ impl MulAssign<Vec3> for Vec3 {
     }
 }
 
-impl MulAssign<f32> for Vec3 {
-    fn mul_assign(&mut self, o: f32) {
+impl MulAssign<f64> for Vec3 {
+    fn mul_assign(&mut self, o: f64) {
         self[0] *= o;
         self[1] *= o;
         self[2] *= o;
     }
 }
 
-impl Mul<f32> for Vec3 {
+impl Mul<f64> for Vec3 {
     type Output = Vec3;
-    fn mul(self, o: f32) -> Vec3 {
+    fn mul(self, o: f64) -> Vec3 {
         Vec3([self[0] * o, self[1] * o, self[2] * o])
     }
 }
@@ -153,17 +153,17 @@ impl Div<Vec3> for Vec3 {
     }
 }
 
-impl Div<f32> for Vec3 {
+impl Div<f64> for Vec3 {
     type Output = Vec3;
 
-    fn div(self, o: f32) -> Vec3 {
+    fn div(self, o: f64) -> Vec3 {
         let o = 1.0 / o;
         Vec3([self[0] * o, self[1] * o, self[2] * o])
     }
 }
 
-impl DivAssign<f32> for Vec3 {
-    fn div_assign(&mut self, o: f32) {
+impl DivAssign<f64> for Vec3 {
+    fn div_assign(&mut self, o: f64) {
         let o = 1.0 / o;
         self.0[0] *= o;
         self.0[1] *= o;
@@ -172,15 +172,15 @@ impl DivAssign<f32> for Vec3 {
 }
 
 impl Index<usize> for Vec3 {
-    type Output = f32;
+    type Output = f64;
 
-    fn index(&self, q: usize) -> &f32 {
+    fn index(&self, q: usize) -> &f64 {
         &self.0[q]
     }
 }
 
 impl IndexMut<usize> for Vec3 {
-    fn index_mut(&mut self, q: usize) -> &mut f32 {
+    fn index_mut(&mut self, q: usize) -> &mut f64 {
         &mut self.0[q]
     }
 }