I've been using the DFT and FFT for so long in my work as an electrical engineer, I sometimes forget the beauty of underlying concepts and equations, especially

I've been using the DFT and FFT for so long in my work as an electrical engineer, I sometimes forget the beauty of underlying concepts and equations, especially since one need not ever code one up as implementations exist in just about every computer language there is. That such a simple equation has such a profound impact on modern life is wonderful.