A code breaking board game in the 1970's. To play the game, a code maker selects a sequence of four colors, represented by colored pegs that come in 6 different colors. The opponent must guess the code-maker's secret sequence, with as few guesses as possible. Each guess is presented in the form of 4 colored pegs.
Since science is connecting thoughts and color, I wonder if this would be a good exercise for psychic ability.