diff --git a/src/fill/factory.rs b/src/fill/factory.rs
new file mode 100644
index 0000000..0abe083
--- /dev/null
+++ b/src/fill/factory.rs
@@ -0,0 +1,81 @@
+use clap::ArgEnum;
+use rand::prelude::IteratorRandom;
+use rand::Rng;
+use crate::fill::FillMode;
+use crate::fill::level::LevelFillMode;
+use crate::vec::Vector;
+
+#[derive(Copy, Clone, ArgEnum)]
+pub enum FillModeEnum {
+    Circle,
+    Level,
+    Stripe
+}
+
+pub trait FillModeFactory {
+    fn create(&self, mode: FillModeEnum, size: Vector) -> Box<dyn FillMode>;
+
+    fn choose(&self, options: Vec<FillModeEnum>, rng: &mut impl Rng) -> FillModeEnum;
+}
+
+pub struct SimpleFillModeFactory;
+
+impl SimpleFillModeFactory {
+    pub fn new() -> Self {
+        Self { }
+    }
+}
+
+impl FillModeFactory for SimpleFillModeFactory {
+    fn create(&self, mode: FillModeEnum, _: Vector) -> Box<dyn FillMode> {
+        match mode {
+            FillModeEnum::Circle => todo!(),
+            FillModeEnum::Level => Box::new(LevelFillMode::new()),
+            FillModeEnum::Stripe => todo!()
+        }
+    }
+
+    fn choose(&self, mut options: Vec<FillModeEnum>, rng: &mut impl Rng) -> FillModeEnum {
+        if options.is_empty() {
+            options.push(FillModeEnum::Circle);
+            options.push(FillModeEnum::Level);
+            options.push(FillModeEnum::Stripe);
+        }
+        options.into_iter().choose_stable(rng).unwrap()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use rand::rngs::mock::StepRng;
+    use super::*;
+
+    #[test]
+    fn create() {
+        let factory = SimpleFillModeFactory::new();
+        let size = Vector::ZERO;
+
+        factory.create(FillModeEnum::Circle, size);
+        factory.create(FillModeEnum::Level, size);
+        factory.create(FillModeEnum::Stripe, size);
+    }
+
+    #[test]
+    fn choose_from_all() {
+        let rng = &mut StepRng::new(0, 1);
+
+        let factory = SimpleFillModeFactory::new();
+
+        assert!(matches!(factory.choose(Vec::new(), rng), FillModeEnum::Stripe));
+    }
+
+    #[test]
+    fn choose_from_options() {
+        let rng = &mut StepRng::new(0, 1);
+        let options = vec![FillModeEnum::Circle];
+
+        let factory = SimpleFillModeFactory::new();
+
+        assert!(matches!(factory.choose(options, rng), FillModeEnum::Circle));
+    }
+}
\ No newline at end of file
diff --git a/src/fill/mod.rs b/src/fill/mod.rs
index 83505f3..c5d4c6c 100644
--- a/src/fill/mod.rs
+++ b/src/fill/mod.rs
@@ -1,42 +1,11 @@
 mod level;
 
-use clap::ArgEnum;
-use rand::prelude::IteratorRandom;
-use rand::Rng;
-use crate::fill::level::LevelFillMode;
+pub mod factory;
+
 use crate::vec::Vector;
 
 /// Used to choose the colors of characters.
 pub trait FillMode {
     /// Gets the color for this character.
-    /// # Arguments
-    /// * `level`:
-    /// * `pos`:
-    ///
-    /// returns: f32
     fn sample(&self, level: f32, pos: Vector) -> f32;
-}
-
-#[derive(Copy, Clone, ArgEnum)]
-pub enum FillModeEnum {
-    Circle,
-    Level,
-    Stripe
-}
-
-pub fn choose_fill_mode(mut options: Vec<FillModeEnum>, rng: &mut impl Rng) -> FillModeEnum {
-    if options.is_empty() {
-        options.push(FillModeEnum::Circle);
-        options.push(FillModeEnum::Level);
-        options.push(FillModeEnum::Stripe);
-    }
-    options.into_iter().choose(rng).unwrap()
-}
-
-pub fn create_fill_mode(mode: FillModeEnum, _: Vector) -> Box<dyn FillMode> {
-    match mode {
-        FillModeEnum::Circle => todo!(),
-        FillModeEnum::Level => Box::new(LevelFillMode::new()),
-        FillModeEnum::Stripe => todo!()
-    }
 }
\ No newline at end of file
diff --git a/src/vec.rs b/src/vec.rs
index 237f74c..90ce8d4 100644
--- a/src/vec.rs
+++ b/src/vec.rs
@@ -6,7 +6,9 @@ pub struct Vector {
 }
 
 impl Vector {
-    pub fn new(x: f32, y: f32) -> Self {
+    pub const ZERO: Vector = Vector::new(0.0, 0.0);
+
+    pub const fn new(x: f32, y: f32) -> Self {
         Self { x, y }
     }
 
@@ -15,6 +17,45 @@ impl Vector {
     /// * `x`: The x axis of the terminal character.
     /// * `y`: The y axis of the terminal character.
     pub fn from_terminal(x: usize, y: usize) -> Self {
-        Vector::new(x as f32, y as f32 * 2.0)
+        Self::new(x as f32, y as f32 * 2.0)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn new() {
+        let vec = Vector::new(3.0, 5.0);
+
+        assert_eq!(3.0, vec.x);
+        assert_eq!(5.0, vec.y);
+    }
+
+    #[test]
+    fn from_terminal() {
+        let vec = Vector::from_terminal(2, 4);
+
+        assert_eq!(2.0, vec.x);
+        assert_eq!(8.0, vec.y);
+    }
+
+    #[test]
+    fn copy() {
+        let vec = Vector::new(2.0, 4.0);
+        let copy = vec;
+
+        assert_eq!(vec.x, copy.x);
+        assert_eq!(vec.y, copy.y);
+    }
+
+    #[test]
+    fn clone() {
+        let vec = Vector::new(2.0, 4.0);
+        let clone = vec.clone();
+
+        assert_eq!(vec.x, clone.x);
+        assert_eq!(vec.y, clone.y);
     }
 }
\ No newline at end of file