If you haven’t seen 3Blue1Brown videos yet, you are missing out! His latest one is on M.C. Escher’s picture frame distortion is absolutely breathtaking, using visuals to introduce complex analysis in what feels a very intuitive way. All his videos are excellent and well worth a browse.

M.C. Escher's The Picture Gallery shows a highly distorted image of a continuously zoomed image, and the conformal mapping to a plane with infinitely tiled copied of this distorted image.
Matthew Kenworthy @kenworthy