Mastermind is a game of guessing codes. Each round, the app will generate a secret combination of colored dots, and it's your job to guess it in fewer than 8 tries. Tap the bottom buttons to cycle through the 6 available colors, and swipe to the right to submit your guess. A white dot means that one of your colors is correct but incorrectly placed, and a black dot means that one of your colors is correct, and correctly placed.