Ha, I have a long-term goal of figuring out Fourier analysis and suspected that it was the trick mentioned in the headline. I can't be bothered to take a class, and textbooks are just too heavy. The Wikipedia article should be helpful, but it is not written as a lesson and has an intimidating presentation.

Years ago I printed out the tutorials at complextoreal.com and have carried them around to the point that they are heavily annotated and tattered. They are not perfect, but they take a friendly, baby-steps approach which I find quite agreeable. Every so often I pick them up and try to make a little more progress. The conversational clarity reminds me of Feynman's presentation style.

For example, the "prism" described in this article (which is more clear as an animation than a series of stills) makes sense to me now, but I don't think I would have followed it without the patient description in Fourier Analysis Made Easy, Chapter 1.

Eventually there is no avoiding the complex representation of the Fourier Equation —

— described as "a most useful albeit a scary looking form." But by the time you encounter this monster you have been well-prepared.

The author, Charan Langton, gave an interview memorably describing what happens to satellite engineers who wear a skirt and heels.