It reminds me of the routing for an integrated circuit to do a Fast Fourier Transform. The butterfly operation on which an FFT is based involves a crossover, s

It reminds me of the routing for an integrated circuit to do a Fast Fourier Transform. The butterfly operation on which an FFT is based involves a crossover, so the basic problem in routing a planar chip is how to make all those crossed over connections. It would be pretty cool if the brain was doing an FFT!