There are 36 buttons in this puzzle.
Touch any button, and then touch another button. If the two numbers that appear are the same, your guess is correct. If they are not, the numbers will be darkened again. The puzzle will be completed when all 18 pairs of numbers have been guessed, and the best time will be recorded.
Each time the game is restarted, the puzzle will randomly assign new numbers.
Note: This puzzle contains 4 1s, 4 2s, and so on, up to 4 9s, to complete a total of 4x9 = 36 circles.