[nograpes]

I appreciate that others may not have got much out of this, but let me say that as someone who knows about statistical modeling, but has no physics training, this made Fourier transforms very clear.

There was another comment that referred to why we use this orthonormal basis versus another, and I think to appreciate the full reason of why this was done in the first place is important. But this presentation is a very good introduction for someone with my particular training.