diff --git a/examples/cubic_bezier.cr b/examples/cubic_bezier.cr
index 1ecbaa6..5b0971b 100644
--- a/examples/cubic_bezier.cr
+++ b/examples/cubic_bezier.cr
@@ -3,7 +3,13 @@ require "../src/bezier"
 
 module PF
   class CubicBezier < PF::Game
-    @curve : BezierCubic(Float64)
+    FONT_COLOR  = Pixel.new(0xFFFFFFFF)
+    POINT_COLOR = Pixel.new(0xFF0000FF)
+    CTL_COLOR   = Pixel.new(0x505050FF)
+    CURVE_COLOR = Pixel.new(0x0077FFFF)
+    SEL_COLOR   = Pixel.new(0xFFFF00FF)
+
+    @curve : Bezier::Cubic(Float64)
 
     @hover_point : Vector2(Float64)*? = nil
     @selected_point : Vector2(Float64)*? = nil
@@ -12,29 +18,15 @@ module PF
 
     def initialize(*args, **kwargs)
       super
-      @curve = BezierCubic.new(
-        Vector[width * 0.25, height * 0.75],
-        Vector[width * 0.33, height * 0.5],
-        Vector[width * 0.66, height * 0.5],
-        Vector[width * 0.75, height * 0.75]
+      @curve = Bezier::Cubic.new(
+        Vector[width * 0.25, height * 0.7],
+        Vector[width * 0.33, height * 0.3],
+        Vector[width * 0.66, height * 0.3],
+        Vector[width * 0.75, height * 0.7]
       )
-
-      @controller = PF::Controller(Keys).new({
-        Keys::KEY_1 => "p1",
-        Keys::KEY_2 => "p2",
-        Keys::KEY_3 => "p3",
-        Keys::KEY_4 => "p4",
-
-        Keys::UP    => "up",
-        Keys::LEFT  => "left",
-        Keys::DOWN  => "down",
-        Keys::RIGHT => "right",
-      })
     end
 
     def update(dt, event)
-      @controller.map_event(event)
-
       case event
       when SDL::Event::MouseButton
         if event.pressed? && event.button == 1
@@ -59,29 +51,24 @@ module PF
     def draw
       clear
 
-      draw_line(@curve.p0, @curve.p1, Pixel.new(100, 100, 100))
-      draw_line(@curve.p3, @curve.p2, Pixel.new(100, 100, 100))
+      draw_line(@curve.p0, @curve.p1, CTL_COLOR)
+      draw_line(@curve.p3, @curve.p2, CTL_COLOR)
 
-      point = @curve.p0
-      0.upto(100) do |x|
-        t = x / 100
-        next_point = @curve.at(t)
-        draw_line(point.to_i, next_point.to_i, Pixel.white)
-        point = next_point
-      end
+      draw_string("Length: " + @curve.length.round(2).to_s, 5, 5, FONT_COLOR)
+      draw_curve(@curve, CURVE_COLOR)
 
-      fill_circle(@curve.p0.to_i, 1, Pixel.blue)
-      fill_circle(@curve.p1.to_i, 1, Pixel.blue)
-      fill_circle(@curve.p2.to_i, 1, Pixel.blue)
-      fill_circle(@curve.p3.to_i, 1, Pixel.blue)
+      fill_circle(@curve.p0.to_i, 2, POINT_COLOR)
+      fill_circle(@curve.p1.to_i, 2, POINT_COLOR)
+      fill_circle(@curve.p2.to_i, 2, POINT_COLOR)
+      fill_circle(@curve.p3.to_i, 2, POINT_COLOR)
 
-      draw_string("P1", @curve.p0.to_i, Pixel.white)
-      draw_string("P2", @curve.p1.to_i, Pixel.white)
-      draw_string("P3", @curve.p2.to_i, Pixel.white)
-      draw_string("P4", @curve.p3.to_i, Pixel.white)
+      draw_string("P1", @curve.p0.to_i, color: FONT_COLOR)
+      draw_string("P2", @curve.p1.to_i, color: FONT_COLOR)
+      draw_string("P3", @curve.p2.to_i, color: FONT_COLOR)
+      draw_string("P4", @curve.p3.to_i, color: FONT_COLOR)
 
       if point = @hover_point
-        draw_circle(point.value.to_i, 5, Pixel.yellow)
+        draw_circle(point.value.to_i, 5, SEL_COLOR)
       end
     end
   end
diff --git a/examples/snow.cr b/examples/snow.cr
index 0872574..54588c4 100644
--- a/examples/snow.cr
+++ b/examples/snow.cr
@@ -15,7 +15,7 @@ class Wind
     property position : PF::Vector2(Float64)
     property strength : PF::Vector2(Float64)
 
-    def initialize(@position, @strength)
+    def initialize(@position, @strength = PF::Vector[rand(-5.0..5.0), rand(-5.0..5.0)])
     end
   end
 
@@ -33,7 +33,7 @@ class Wind
     while y < @height
       x = step / 2
       while x < @width
-        @gusts << Gust.new(PF::Vector[x, y], PF::Vector[rand(-1.0..1.0), rand(-1.0..1.0)])
+        @gusts << Gust.new(PF::Vector[x, y])
         x += step
       end
       y += step
@@ -48,11 +48,11 @@ class Flake
   property velocity : PF::Vector2(Float64)
 
   def initialize(@position, @shape = rand(0_u8..2_u8), @z_pos = rand(0.0..1.0), velocity : PF::Vector2(Float64)? = nil)
-    @velocity = velocity || PF::Vector[rand(-2.0..2.0), rand(0.0..20.0)]
+    @velocity = velocity || PF::Vector[rand(-2.0..2.0), rand(10.0..20.0)]
   end
 
   def update(dt)
-    @velocity.y = @velocity.y + 1.0 * dt
+    @velocity.y = @velocity.y + 5.0 * dt
     @position += @velocity * dt
   end
 end
@@ -66,6 +66,9 @@ class Snow < PF::Game
     super
 
     @wind = Wind.new(@width, @height)
+    500.times do
+      @flakes << Flake.new(position: PF::Vector[rand(0.0..@width.to_f64), rand(0.0..@height.to_f64)])
+    end
     clear(0, 0, 15)
   end
 
diff --git a/src/bezier.cr b/src/bezier.cr
index 2fdf724..6c17000 100644
--- a/src/bezier.cr
+++ b/src/bezier.cr
@@ -1 +1,24 @@
+module PF
+  module Bezier
+    alias Curve = Quad(Float64) | Cubic(Float64)
+
+    module Aproximations
+      # Get the length of the curve by calculating the length of line segments
+      # Increase *steps* for accuracy
+      def length(steps : UInt32 = 10)
+        _length = 0.0
+        seg_p0 = Vector[@p0.x, @p0.y]
+
+        0.upto(steps) do |n|
+          t = n / steps
+          seg_p1 = at(t)
+          _length += seg_p0.distance(seg_p1)
+          seg_p0 = seg_p1
+        end
+        _length
+      end
+    end
+  end
+end
+
 require "./bezier/*"
diff --git a/src/bezier/cubic.cr b/src/bezier/cubic.cr
index 1ea98b0..7774d81 100644
--- a/src/bezier/cubic.cr
+++ b/src/bezier/cubic.cr
@@ -1,48 +1,57 @@
 require "../bezier"
 
 module PF
-  struct BezierCubic(T)
-    def self.point(t : Float64, p0 : Number, p1 : Number, p2 : Number, p3 : Number)
-      (1 - t) ** 3 * p0 + 3 * (1 - t) ** 2 * t * p1 + 3 * (1 - t) * t ** 2 * p2 + t ** 3 * p3
-    end
+  module Bezier
+    struct Cubic(T)
+      include Aproximations
 
-    property p0 : Vector2(T)
-    property p1 : Vector2(T)
-    property p2 : Vector2(T)
-    property p3 : Vector2(T)
-
-    def initialize(@p0 : Vector2(T), @p1 : Vector2(T), @p2 : Vector2(T), @p3 : Vector2(T))
-    end
-
-    def [](index : Int)
-      points[index]
-    end
-
-    def points
-      {pointerof(@p0), pointerof(@p1), pointerof(@p2), pointerof(@p3)}
-    end
-
-    # Get the point at percentage *t* of the curve
-    def at(t : Float64)
-      Vector[
-        BezierCubic.point(t, @p0.x, @p1.x, @p2.x, @p3.x),
-        BezierCubic.point(t, @p0.y, @p1.y, @p2.y, @p3.y),
-      ]
-    end
-
-    # Get the length of the curve by calculating the length of line segments
-    def length(steps : UInt32 = 10)
-      _length = 0.0
-      seg_p0 = Vector[@p0.x, @p0.y]
-      seg_p1 = uninitialized Vector2(T)
-
-      0.upto(steps) do |n|
-        t = n / steps
-        seg_p1 = at(t)
-        _length += seg_p0.distance(seg_p1)
-        seg_p0 = seg_p1
+      def self.point(t : Float64, p0 : Number, p1 : Number, p2 : Number, p3 : Number)
+        (1 - t) ** 3 * p0 + 3 * (1 - t) ** 2 * t * p1 + 3 * (1 - t) * t ** 2 * p2 + t ** 3 * p3
+      end
+
+      def self.derivative(t : Float64, p0 : Number, p1 : Number, p2 : Number, p3 : Number)
+        3 * (1 - t) ** 2 * (p1 - p0) + 6 * (1 - t) * t * (p2 - p1) + 3 * t ** 2 * (p3 - p2)
+      end
+
+      def self.second_derivative(t : Float64, p0 : Number, p1 : Number, p2 : Number, p3 : Number)
+        6 * (1 - t) * (p2 - 2 * p1 + p0) + 6 * t * (p3 - 2 * p2 + p1)
+      end
+
+      property p0 : Vector2(T)
+      property p1 : Vector2(T)
+      property p2 : Vector2(T)
+      property p3 : Vector2(T)
+
+      def initialize(@p0 : Vector2(T), @p1 : Vector2(T), @p2 : Vector2(T), @p3 : Vector2(T))
+      end
+
+      def points
+        {pointerof(@p0), pointerof(@p1), pointerof(@p2), pointerof(@p3)}
+      end
+
+      # Get the point at percentage *t* < 0 < 1 of the curve
+      def at(t : Float64)
+        Vector[
+          T.new(self.class.point(t, @p0.x, @p1.x, @p2.x, @p3.x)),
+          T.new(self.class.point(t, @p0.y, @p1.y, @p2.y, @p3.y)),
+        ]
+      end
+
+      # Get the tangent to a point at *t* < 0 < 1 on the spline
+      def tangent(t : Float64)
+        Vector[
+          T.new(self.class.derivative(t, @p0.x, @p1.x, @p2.x, @p3.x)),
+          T.new(self.class.derivative(t, @p0.y, @p1.y, @p2.y, @p3.y)),
+        ].normalized
+      end
+
+      # Get the normal to a point at *t* < 0 < 1 on the spline
+      def normal(t : Float64)
+        Vector[
+          T.new(self.class.derivative(t, @p0.y, @p1.y, @p2.y, @p3.y)),
+          T.new(-self.class.derivative(t, @p0.x, @p1.x, @p2.x, @p3.x)),
+        ].normalized
       end
-      _length
     end
   end
 end
diff --git a/src/bezier/quad.cr b/src/bezier/quad.cr
index a16773f..6d1ed9b 100644
--- a/src/bezier/quad.cr
+++ b/src/bezier/quad.cr
@@ -1,45 +1,30 @@
 module PF
-  struct BezierQuad(T)
-    def self.point(t : Float64, p0 : Number, p1 : Number, p2 : Number)
-      (1 - t) ** 2 * p0 + 2 * (1 - t) * t * p1 + t ** 2 * p2
-    end
+  module Bezier
+    struct Quad(T)
+      include Aproximations
 
-    property p0 : Vector2(T)
-    property p1 : Vector2(T)
-    property p2 : Vector2(T)
-
-    def initialize(@p0 : Vector2(T), @p1 : Vector2(T), @p2 : Vector2(T))
-    end
-
-    def [](index : Int)
-      points[index]
-    end
-
-    def points
-      {pointerof(@p0), pointerof(@p1), pointerof(@p2)}
-    end
-
-    # Get the point at percentage *t* of the curve
-    def at(t : Float64)
-      Vector[
-        BezierQuad.point(t, @p0.x, @p1.x, @p2.x),
-        BezierQuad.point(t, @p0.y, @p1.y, @p2.y),
-      ]
-    end
-
-    # Get the length of the curve by calculating the length of line segments
-    def length(steps : UInt32 = 10)
-      _length = 0.0
-      seg_p0 = Vector[@p0.x, @p0.y]
-      seg_p1 = uninitialized Vector2(T)
-
-      0.upto(steps) do |n|
-        t = n / steps
-        seg_p1 = at(t)
-        _length += seg_p0.distance(seg_p1)
-        seg_p0 = seg_p1
+      def self.point(t : Float64, p0 : Number, p1 : Number, p2 : Number)
+        (1 - t) ** 2 * p0 + 2 * (1 - t) * t * p1 + t ** 2 * p2
+      end
+
+      property p0 : Vector2(T)
+      property p1 : Vector2(T)
+      property p2 : Vector2(T)
+
+      def initialize(@p0 : Vector2(T), @p1 : Vector2(T), @p2 : Vector2(T))
+      end
+
+      def points
+        {pointerof(@p0), pointerof(@p1), pointerof(@p2)}
+      end
+
+      # Get the point at percentage *t* of the curve
+      def at(t : Float64)
+        Vector[
+          self.class.point(t, @p0.x, @p1.x, @p2.x),
+          self.class.point(t, @p0.y, @p1.y, @p2.y),
+        ]
       end
-      _length
     end
   end
 end
diff --git a/src/game.cr b/src/game.cr
index 394c81e..d8ea6c7 100644
--- a/src/game.cr
+++ b/src/game.cr
@@ -17,7 +17,7 @@ module PF
     property running = true
     property screen : Sprite
 
-    delegate :draw_point, :draw_line, :scan_line, :draw_circle, :draw_triangle, :draw_rect, :draw_shape,
+    delegate :draw_point, :draw_line, :draw_curve, :scan_line, :draw_circle, :draw_triangle, :draw_rect, :draw_shape,
       :fill_triangle, :fill_rect, :fill_circle, :fill_shape, :draw_string, to: @screen
 
     @fps_lasttime : Float64 = Time.monotonic.total_milliseconds # the last recorded time.
diff --git a/src/pixel.cr b/src/pixel.cr
index 65b4011..ff10456 100644
--- a/src/pixel.cr
+++ b/src/pixel.cr
@@ -39,10 +39,10 @@ module PF
     property r : UInt8, g : UInt8, b : UInt8, a : UInt8
 
     def initialize(rgba : UInt32)
-      @r = ((rgba >> 24) & 0xFF).to_u8
-      @g = ((rgba >> 16) & 0xFF).to_u8
-      @b = ((rgba >> 8) & 0xFF).to_u8
-      @a = (rgba & 0xFF).to_u8
+      @r = (rgba >> 24).to_u8!
+      @g = (rgba >> 16).to_u8!
+      @b = (rgba >> 8).to_u8!
+      @a = (rgba).to_u8!
     end
 
     def initialize(@r : UInt8 = 255, @g : UInt8 = 255, @b : UInt8 = 255, @a : UInt8 = 255)
@@ -73,6 +73,7 @@ module PF
     end
 
     def to_u32
+      value = uninitialized UInt32
       value = @r.to_u32 << 24
       value |= @g.to_u32 << 16
       value |= @b.to_u32 << 8
diff --git a/src/sprite.cr b/src/sprite.cr
index 3d50c91..3d349a9 100644
--- a/src/sprite.cr
+++ b/src/sprite.cr
@@ -117,7 +117,8 @@ module PF
     end
 
     # Sample a color with alhpa
-    def sample(x : Int, y : Int, alpha = true)
+    def sample(x : Int, y : Int, alpha : Boolean)
+      return sample(x, y) unless alpha
       raw_pixel = pixel_pointer(x, y).value
 
       r = uninitialized UInt8
@@ -130,13 +131,13 @@ module PF
     end
 
     # ditto
-    def sample(point : Vector2(Int), alpha = true)
-      sample(point.x, point.y, true)
+    def sample(point : Vector2(Int), alpha : Boolean)
+      sample(point.x, point.y, alpha)
     end
 
     # Get the pointer to a pixel
     def pixel_pointer(x : Int32, y : Int32)
-      target = @surface.pixels + (y * @surface.pitch) + (x * 4)
+      target = @surface.pixels + (y * @surface.pitch) + (x * sizeof(UInt32))
       target.as(Pointer(UInt32))
     end
   end
diff --git a/src/sprite/draw_curve.cr b/src/sprite/draw_curve.cr
new file mode 100644
index 0000000..17cde36
--- /dev/null
+++ b/src/sprite/draw_curve.cr
@@ -0,0 +1,17 @@
+module PF
+  class Sprite
+    def draw_curve(curve : Bezier::Cubic, samples : Int = 100, pixel : Pixel = Pixel.new)
+      point = curve.p0
+      0.upto(samples) do |x|
+        t = x / samples
+        next_point = curve.at(t)
+        draw_line(point.to_i, next_point.to_i, pixel)
+        point = next_point
+      end
+    end
+
+    def draw_curve(curve : Bezier::Cubic, pixel : Pixel)
+      draw_curve(curve, pixel: pixel)
+    end
+  end
+end
diff --git a/src/sprite/draw_string.cr b/src/sprite/draw_string.cr
index dce6ec9..c252a0c 100644
--- a/src/sprite/draw_string.cr
+++ b/src/sprite/draw_string.cr
@@ -94,10 +94,9 @@ module PF
     CHAR_WIDTH  = 7
     CHAR_HEIGHT = 8
 
-    def draw_string(msg : String, x : Int, y : Int, color : Pixel = Pixel.black, bg : Pixel? = nil)
+    def draw_string(msg : String, x : Int, y : Int, color : Pixel = Pixel.new, bg : Pixel? = nil, leading : Int = 2)
       cur_y = 0
       cur_x = 0
-      leading = 2
 
       msg.chars.each do |c|
         if c == '\n'