Fourier transformations clicked for me from your previous articles, this outline really shows the skill of "sharpening" rather than "building" knowledge. Helpful for young kids to adults alike.
I had the same experience. However later when I encountered new properties of fourier transforms, such as the convolution theorem, fast fourier transform and the fourier transform of boolean functions, I felt my acquired intuition no longer fitted. Did you also experience this? If so, how did you get past it to that "next level"?