Here's how to properly explain the fast Fourier transform, or FFT:
Okay, it's a Fourier transform, or FT, right, but while you're doing it, you fold the buckets and the coefficients like origami, see, yes, basically like a unicorn, so you have to cut the code here, and here, and here so the head will come out right, yes, that's it, and this code over here, it only runs if the unicorn is facing south, plus, you pull its tail so it makes little unicorn poops, and those have to go back into the unicorn's little feed bin for next time around, because otherwise, the feedbin is too sweet, see, and the buckets are all funny-like and time goes back to being partially frequency. And you don't want that.
So that's it, yeah, and I'll need your code example by tomorrow morning. Class dismissed.