Memory training on a grid where a few squares light up and then go out. Find the same squares. After a mistake-free round one more square lights up in the next round, and after a mistake one fewer. After your first mistake the number of squares grows only after two mistake-free rounds in a row, and after your second mistake only after three. A game has 25 rounds.
Before the game, choose whether the squares light up all at once or one at a time. Squares that light up all at once you find in any order, and squares that light up one at a time in the same order. A mistake-free round scores as many points as there were squares, and a quick answer earns bonus points. A round with a mistake scores nothing.