diff --git a/src/hittable.rs b/src/hittable.rs
index 0b9097a..877b294 100644
--- a/src/hittable.rs
+++ b/src/hittable.rs
@@ -4,8 +4,9 @@ use super::Vec3;
 
 pub struct HitRecord {
     p: Point3,
-    normal: Vec3,
-    t: f64,
+    pub normal: Vec3,
+    pub t: f64,
+    front_face: bool,
 }
 
 pub struct Sphere {
@@ -14,11 +15,35 @@ pub struct Sphere {
 }
 
 pub trait Hittable {
-    fn hit(&self, r: Ray, t_min: f64, t_max: f64, rec: &mut HitRecord) -> bool;
+    fn hit(&self, r: &Ray, t_min: f64, t_max: f64, rec: &mut HitRecord) -> bool;
+}
+
+impl HitRecord {
+    fn set_face_normal(&mut self, r: &Ray, outward_normal: Vec3) {
+        self.front_face = Vec3::dot(r.direction(), outward_normal) < 0.0;
+        if self.front_face {
+            self.normal = outward_normal;
+        } else {
+            self.normal = (-1.0)*outward_normal;
+        }
+    }
+
+    pub fn new(p: Point3, normal: Vec3, t: f64, front_face: bool) -> Self {
+        HitRecord {
+            p: p,
+            normal: normal,
+            t: t,
+            front_face: front_face,
+        }
+    }
+
+    pub fn empty() -> Self {
+        Self::new(Point3::new(0.0,0.0,0.0), Vec3::new(0.0,0.0,0.0), 0.0, false)
+    }
 }
 
 impl Sphere {
-    fn new(cen: Point3, r: f64) -> Self {
+    pub fn new(cen: Point3, r: f64) -> Self {
         Sphere {
             center: cen,
             radius: r,
@@ -27,22 +52,22 @@ impl Sphere {
 }
 
 impl Hittable for Sphere {
-    fn hit(&self, r: Ray, t_min: f64, t_max: f64, rec: &mut HitRecord) -> bool {
+    fn hit(&self, r: &Ray, t_min: f64, t_max: f64, rec: &mut HitRecord) -> bool {
         let oc = r.origin() - self.center;
         let a = r.direction().length_squared(); // gleiches Ergebnis wie Skalarprodukt
-        let b = 2.0 * Vec3::dot(oc, r.direction());
+        let half_b = Vec3::dot(oc, r.direction());
         let c = oc.length_squared() - self.radius * self.radius;
 
-        let discriminant = b * b - 4.0 * a * c;
+        let discriminant = half_b * half_b - a * c;
         if discriminant < 0.0 {
             return false;
         }
 
         let sqrtd = discriminant.sqrt();
 
-        let root = (-b / 2.0 - sqrtd) / a;
+        let root = (-half_b - sqrtd) / a;
         if root < t_min || t_max < root {
-            let root2 = (-b / 2.0 + sqrtd) / a;
+            let root2 = (-half_b + sqrtd) / a;
             if root2 < t_min || t_max < root {
                 return false;
             }
@@ -50,7 +75,8 @@ impl Hittable for Sphere {
 
         rec.t = root;
         rec.p = r.at(rec.t);
-        rec.normal = (rec.p - self.center) / self.radius;
+        let outward_normal = (rec.p - self.center) / self.radius;
+        rec.set_face_normal(r, outward_normal);
 
         return true;
     }
diff --git a/src/hittable_list.rs b/src/hittable_list.rs
new file mode 100644
index 0000000..05da354
--- /dev/null
+++ b/src/hittable_list.rs
@@ -0,0 +1,40 @@
+use super::Hittable;
+use super::Ray;
+use super::HitRecord;
+
+pub struct HittableList {
+    objects: Vec<Box<dyn Hittable>>,
+}
+
+impl HittableList {
+    pub fn new()-> Self {
+        HittableList {
+            objects: Vec::<Box<dyn Hittable>>::new()
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.objects.clear();
+    }
+
+    pub fn add(&mut self, obj: Box<dyn Hittable>) {
+        self.objects.push(obj);
+    }
+
+    pub fn hit(&self, r: &Ray, t_min: f64, t_max: f64, rec: &mut HitRecord) -> bool {
+        
+        let mut hit_anything = false;
+        let mut closest_so_far = t_max;
+
+        for obj in &self.objects {
+            let mut temp_rec = HitRecord::empty();
+            if obj.hit(&r, t_min, closest_so_far, &mut temp_rec) {
+                hit_anything = true;
+                closest_so_far = temp_rec.t;
+                *rec = temp_rec;
+            }
+        }
+
+        return hit_anything;
+    }
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index ec4cf24..54f36e8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,7 +1,9 @@
 mod color;
 mod hittable;
+mod hittable_list;
 mod ray;
 mod vec3;
+mod utility;
 use ray::Ray;
 use std::env;
 use std::fs::File;
@@ -10,6 +12,10 @@ use std::io::Write;
 use vec3::Color;
 use vec3::Point3;
 use vec3::Vec3;
+use hittable::Hittable;
+use hittable::Sphere;
+use hittable_list::HittableList;
+use hittable::HitRecord;
 
 fn hit_sphere(center: &Point3, radius: f64, r: &Ray) -> f64 {
     let oc = r.origin() - *center;
@@ -25,13 +31,12 @@ fn hit_sphere(center: &Point3, radius: f64, r: &Ray) -> f64 {
     }
 }
 
-fn ray_color(r: &Ray) -> Color {
-    let t = hit_sphere(&Point3::new(0.0, 0.0, -1.0), 0.5, r);
-    if t > 0.0 {
-        let n = Vec3::unit_vector(r.at(t) - Vec3::new(0.0, 0.0, -1.0));
-        return 0.5 * Color::new(n.x() + 1.0, n.y() + 1.0, n.z() + 1.0);
-    }
+fn ray_color(r: &Ray, world: &HittableList) -> Color {
+    let mut rec = HitRecord::empty();
 
+    if world.hit(r, 0.0, f64::INFINITY, &mut rec) {
+        return 0.5 * (rec.normal + Color::new(1.0, 1.0, 1.0));
+    }
     let unit_direction = r.direction();
     let t = 0.5 * (unit_direction.y() + 1.0);
     return (1.0 - t) * Color::new(1.0, 1.0, 1.0) + t * Color::new(0.5, 0.7, 1.0);
@@ -43,9 +48,14 @@ fn main() {
 
     // Image
     let aspect_ratio = 16.0 / 9.0;
-    let image_width = 2000;
+    let image_width = 1000;
     let image_height = (image_width as f64 / aspect_ratio) as u64;
 
+    // World
+    let mut world = HittableList::new();
+    world.add(Box::<Sphere>::new(Sphere::new(Point3::new(0.0, 0.0, -1.0), 0.5)));
+    world.add(Box::<Sphere>::new(Sphere::new(Point3::new(0.0, -100.5, -1.0), 100.0)));
+
     // Camera
     let viewport_height = 2.0;
     let viewport_width = aspect_ratio * viewport_height;
@@ -74,7 +84,7 @@ fn main() {
                 origin,
                 lower_left_corner + u * horizontal + v * vertical - origin,
             );
-            let pixel_color = ray_color(&r);
+            let pixel_color = ray_color(&r, &mut world);
 
             color::write_color(&mut file, pixel_color);
         }
diff --git a/src/utility.rs b/src/utility.rs
new file mode 100644
index 0000000..e69de29