Minecraft wiki entry for Advanced_redstone_circuits, associated text: In the following we'll use (0)16 = (1111)2. And for [1,9] the MUX-table upon. So the key uses decimal digits. Therefore, we have to mux the used buttons to binary data. Here look through the first two columns. The first represents the input-digit in (hexa)decimal, the second represents the input-digit in binary code. Here you can add also buttons for [A,E], but I disclaimed them preferring a better arranging. The /b1\-box outputs the first bit, the /b2\-box the second, and so on.