What do you mean you don't understand binary? Like Terry Nutkins, it only has 2 digits to worry about.... next you're going to tell me you don't get Pi. Anyway, this rather fine Binary Sudoku T-shirt is an ideal present to yourself or for the computer dude in your life that also loves Japanese number puzzles. & in case you were in any doubt, it costs 0011000100110011001011100011100100111001