Your goal is to break a secret code consisting of several randomly chosen items. To achieve that goal you can give a guess and the app will return an answer evaluating your guess. From these answers you have to deduce the secret code in a limited number of rounds.
Each item consists of a shape on a colored field. The classical version of the game does not use shapes at all but confines itself to colored fields alone.
After making a guess for the code the app calculates an answer. It will give you a black pin for each item in your guess that is fully correct. You will get a white pin for each item that fully appears in the secret code, but at another position. If you are using shapes then you will be rewarded by a blue pin for each remaining item that is half correct.
You can easily adapt the difficulty level to your liking: the width of the code, the number of colors and the number of shapes is changable.