Why are a piano’s black keys arranged in groups of three and two?

Question

Why are a piano’s black keys arranged in groups of three and two?

In: 44

Answer 1

The older I get the more elegant it appears. There’s some deep symmetry that arises from this. The most easily seen is that you have (in every octave)

W B W B W

B W B W B

With a tritone separating them (F and B).