Not an image of a CRT with sexy scanlines, but it's a question about shadow masks. Why did almost all shadow masks have the same relative size of vertical blocks (left side)?
Shadow mask - Wikipedia
Shadow Mask CRT - Computer Notes
2.9- Shadow Mask Technique In Color CRT In Computer Graphics Hindi | Color CRT In Computer Graphics - YouTube
Werner Flechsig: First Practical Color CRT, 1938
File:CRT mask types en-de.svg - Wikimedia Commons
CRT shadow-mask pattern" Mask for Sale by Fuzzclone | Redbubble
New CRT shader from Guest + CRT Guest Advanced updates - Shaders - Libretro Forums