diff --git a/example.png b/example.png
index 91701cc..979ba45 100644
Binary files a/example.png and b/example.png differ
diff --git a/src/main.rs b/src/main.rs
index f4aa9e9..d6d7d29 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -28,15 +28,15 @@ use crate::{
 fn random_scene() -> HittableList {
     let mut world = HittableList::new_empty();
 
-    static GROUND_MATERIAL: Lambertian = Lambertian::new(Color::new(0.5, 0.5, 0.5));
+    let ground_material: Lambertian = Lambertian::new(Color::new(0.5, 0.5, 0.5));
     world.add(Box::new(Sphere::new(
         Point3::new(0.0, -1000.0, 0.0),
         1000.0,
-        &GROUND_MATERIAL,
+        Box::new(ground_material),
     )));
 
-    for a in 0..12 {
-        for b in 0..12 {
+    for a in -12..12 {
+        for b in -12..12 {
             let choose_mat = random_f64();
             let center = Point3::new(
                 a as f64 + 0.9 * random_f64(),
@@ -47,38 +47,38 @@ fn random_scene() -> HittableList {
             if (center - Point3::new(4.0, 0.2, 0.0)).length() > 0.9 {
                 if choose_mat < 0.8 {
                     //let albedo = Color::new(0.3, 0.8, 0.4);
-                    static SPHERE_MATERIAL: Lambertian = Lambertian::new(Color::new(0.3, 0.8, 0.4));
-                    world.add(Box::new(Sphere::new(center, 0.2, &SPHERE_MATERIAL)));
+                    let sphere_material: Lambertian = Lambertian::new(Color::random());
+                    world.add(Box::new(Sphere::new(center, 0.2, Box::new(sphere_material))));
                 } else if choose_mat < 0.95 {
-                    static SPHERE_MATERIAL: Metal = Metal::new(Color::new(0.3, 0.6, 0.2), 0.2);
-                    world.add(Box::new(Sphere::new(center, 0.2, &SPHERE_MATERIAL)));
+                    let sphere_material: Metal = Metal::new(Color::random(), 0.2);
+                    world.add(Box::new(Sphere::new(center, 0.2, Box::new(sphere_material))));
                 } else {
-                    static SPHERE_MATERIAL: Dielectric = Dielectric::new(1.5);
-                    world.add(Box::new(Sphere::new(center, 0.2, &SPHERE_MATERIAL)));
+                    let sphere_material: Dielectric = Dielectric::new(1.5);
+                    world.add(Box::new(Sphere::new(center, 0.2, Box::new(sphere_material))));
                 }
             }
         }
     }
 
-    static MATERIAL1: Dielectric = Dielectric::new(1.5);
+    let material1: Dielectric = Dielectric::new(1.5);
     world.add(Box::new(Sphere::new(
         Point3::new(0.0, 1.0, 0.0),
         1.0,
-        &MATERIAL1,
+        Box::new(material1),
     )));
 
-    static MATERIAL2: Lambertian = Lambertian::new(Color::new(0.4, 0.2, 0.1));
+    let material2: Lambertian = Lambertian::new(Color::new(0.4, 0.2, 0.1));
     world.add(Box::new(Sphere::new(
         Point3::new(-4.0, 1.0, 0.0),
         1.0,
-        &MATERIAL2,
+        Box::new(material2),
     )));
 
-    static MATERIAL3: Metal = Metal::new(Color::new(0.7, 0.6, 0.5), 0.0);
+    let material3: Metal = Metal::new(Color::new(0.7, 0.6, 0.5), 0.0);
     world.add(Box::new(Sphere::new(
         Point3::new(4.0, 1.0, 0.0),
         1.0,
-        &MATERIAL3,
+        Box::new(material3),
     )));
 
     world
@@ -112,10 +112,10 @@ fn ray_color(r: Ray, world: &dyn Hittable, depth: i32) -> Color {
 fn main() {
     // Image
     let aspect_ratio: f64 = 16. / 9.;
-    let image_width: i32 = 2560;
+    let image_width: i32 = 1920;
     let image_height: i32 = (image_width as f64 / aspect_ratio as f64) as i32;
-    let samples_per_pixel: i32 = 5;
-    let max_depth: i32 = 4;
+    let samples_per_pixel: i32 = 200;
+    let max_depth: i32 = 5;
 
     // World
     let world = random_scene();
diff --git a/src/sphere.rs b/src/sphere.rs
index 702e72b..6c9e9e3 100644
--- a/src/sphere.rs
+++ b/src/sphere.rs
@@ -1,21 +1,24 @@
+use std::ops::Deref;
+
 use crate::hittable::*;
 use crate::material::Material;
 use crate::vec3::*;
+use crate::Ray;
 
-pub struct Sphere<'a> {
+pub struct Sphere {
     center: Point3,
     radius: f64,
-    mat_ptr: &'a dyn Material,
+    mat_ptr: Box<dyn Material>,
 }
 
-impl Sphere<'_> {
-    pub fn new<T: Material>(center: Point3, radius: f64, mat_ptr: &'static T) -> Self {
+impl Sphere {
+    pub fn new<T: Material + 'static>(center: Point3, radius: f64, mat_ptr: Box<T>) -> Self {
         Sphere {center, radius, mat_ptr}
     }
 }
 
-impl Hittable for Sphere<'_> {
-    fn hit(&self, r: &crate::ray::Ray, t_min: f64, t_max: f64) -> Option<HitRecord<'_>> {
+impl Hittable for Sphere {
+    fn hit(&self, r: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord<'_>> {
         let oc = r.origin() - self.center;
         let a = r.direction().length_squared();
         let half_b = oc.dot(&r.direction());
@@ -51,7 +54,7 @@ impl Hittable for Sphere<'_> {
             p: p,
             normal: outward_normal,
             front_face,
-            mat_ptr: self.mat_ptr,
+            mat_ptr: self.mat_ptr.deref(),
         })
     }
 }
\ No newline at end of file