[YoshiRulz]

For JPEG compression: https://parametric.press/issue-01/unraveling-the-jpeg/#param... (anchor doesn't work for me, but it's the one with the caption "Move slider to adjust the amount of subsampling applied." which made me understand the motivation behind using chroma)

For polygon sum/union/difference: https://sean.fun/a/polygon-clipping-pt1/ (the diagram captioned "Combined Fill Annotations" at https://sean.fun/a/polygon-clipping-pt2/#annotating-segments is my favourite visual proof)

For cryptanalysis: https://random.tastemaker.design

For Fourier transforms: https://brianmcfee.net/dstbook-site/content/ch05-fourier/Sim...

For digital typesetting of Arabic: https://lr0.org/blog/p/arabic/