ICOSOKU is a brilliant Brainteaser with literally thousands of challenges. First remove all the dotted tiles & number buttons. Then place all 12 number buttons randomly on the Brainteaser. Now position the 20 dotted tiles so that all the dots surrounding each number button add up exactly to the number on the button. You’ve succeeded when you’ve placed all the dotted tiles correctly so the numbers match the surrounding dots, with no dotted tiles left over To create a new challenge simply swop a few number buttons and you have a new challenge to solve! Endless hours of fun!