Youre given a random color, and buttons that control the amount of red, green, and blue values of the background color. As soon as you match the background with the given color, you can reset with a new color and try again. Great for learning how colors work.
The more complex the mode, the more subtle the color changes are. Color values increment differently based on mode and a special slider available in the harder difficulties.
Container views and UIStoryboard allow for multiple modes and difficulties to be displayed on the same view controller.
Theres also zen mode for those who want to just play around with colors without worrying about matching the background to the target.