Oh yeah, I forgot what the table layout stuff used to be like. Since the back has a shine gradient across the back, each position would need all the possible characters. iirc, in that period an article on A List Apart [0] proposed something like that. I think they were doing curved box corners and sending all corners in the same file and using background positioning to only show the portion of the image depicting that corner. As I scan the article it is heavy on CSS positioning, which is used in the demo but I recall IE5 had quirks.

How true to period is the demo? I see in the source "I've tried to preserve the core of this code as it was when I wrote it in June 2005." but most of the page is a static image in the background.

0. https://alistapart.com/article/sprites/