This is an online replica of the game Mastermind, first created by Mordecai Meirowitz in 1970. To begin, simply CLICK each one of the four squares. To cycle through the different colors, continue clicking on the squares until you reach the desired color. All squares must be colored. Once all colors are filled, press SPACE, or click the right-most button. Then, your response will appear above. WHITE pegs represent a guessed color that is correct, but in the wrong location. RED pegs represent a guessed color that is correct, and in the correct location. In order to win, guess the correct combination in under five moves. No color is repeated twice.
You can check it out here.