Is Sudoku too much work for you and a bit of a bore? Say hello toÂ Bitmask, a Soduku inspired puzzle where numbers are replaced with the task of fixing theÂ computer by unmasking the bits. Almost a pattern makingÂ exercise, the catch is that you may not repeat any three-bit pattern within a row or column. You switch bits by adjusting the switches. Some bits are fixed, others allow changes, as the numbers do in Sudoku.