def draw_rectangle(point, size, z_index, colour)
      left    = point.x
      top     = point.y
      width   = size.width
      height  = size.height

      draw_quad(
        left, top, colour,
        left + width, top, colour,
        left + width, top + height, colour,
        left, top + height, colour,
        z_index)
    end
def draw_rectangle(point, size, z_index, colour)
      left    = point.x
      top     = point.y
      width   = size.width
      height  = size.height

      draw_quad(
        left, top, colour,
        left + width, top, colour,
        left + width, top + height, colour,
        left, top + height, colour,
        z_index)
    end
Simplify drawing a rectangle in a single colour.

 * +point+     [Point] Top left corner
 * +size+      [Size] Width and Height
 * +z_index+   [Fixnum] Z-order
 * +colour+    [Gosu::Color] Colour of rectangle