The Many Faces of Life

2^N-N-1

That's the number of different ways that N different people can get together.

Imagine that N is just 3. These three people could create 3 different groups of 2 people and one including all 3 people, a total of 4 groups as the equation predicts. That's a small start but as N gets bigger the number of possible groups grows, at first steadily, and then turns a corner and soars vertically up into the sky.

Alun Anderson