Set of sets: ABCD ABCE AEF DFG ABFG arbitrary set: BG Internally, this is all stored a integers, which I'll write out here in binary: ABCDEFG 1111000 1110100 1000110 0001011 1100011 arbitrary set: 0100001 I'm going to keep using the letters in the rest of the post, though, they're easier to read.