Everything on a computer is bits. Tap the cells to flip bits and see the number change, then run the bitwise operations — AND, OR, XOR, NOT, shifts — that power everything from colours to cryptography.
Each bit is a power of two: 128·64·32·16·8·4·2·1, so 8 bits represent 0–255. AND keeps a bit only if both have it (used in masking). OR keeps it if either has it. XOR keeps it if exactly one has it (used in checksums and graphics). << and >> shift bits left/right — shifting left doubles the number. Two's complement is how negatives are stored: −A is stored as 256 − A.