Technically, it isn’t a BCD (Binary Coded Decimal) watch. The minutes on this watch are displayed in pure binary, e.g., 32, 16, 8, 4, 2, 1, while if BCD, it would be 4, 2, 1 (tens digit), then 8 ...

LEGO binary to decimal conversion [Carl] is doing a few experiments to see if it’s possible to build a calculating machine out of LEGO. He managed to convert four bits of binary into decimal .