I'm trying to diagramize some colour swatches at work, and I wanted a pattern that could be scaled up to n colours while still being symmetrical. The key is to ensure that every colour has every other colour as a neighbour. Possible? Here's what I mean: 2 colours: a pie cut into 2 pieces, one of each colour. Both pieces are the same shape, both are bordered by the other colour(s). 3 colours: a pie cut into 3 pieces, one of each colour. All 3 pieces are the same shape, all have every other colour as a neighbour. 4 colours: a pie cut into 4 pieces, one of each of 4 colours. But 2 pairs colours do not share a border, sinced they're kitty corner. (It is possible to do it by moving into the 3rd dimension - a tetrahedron will do nicely, but that's cheating.) Is there a way of making a pattern (no matter how complex or convoluted) such that each colour has the same shape (tile), and each borders every other? And is in only 2-dimensions? What is the maximum number of colours that one can accomodate? I doubt there's anything practical that I could use at work, but now I have an academic curiosity.