But what is the Fourier Transform? A visual introduction

youtube.com

Oh boy was that well presented. I wish I had seen this when I studied signal processing.

Same! I feel that this 20 min video reached an intuition level that is equivalent to what were probably a couple of months of my ECE undergrad.

Later duplicate that ended up on the front page: https://news.ycombinator.com/item?id=16242103