Gotta love the B&W bitmap graphics in the OpenType spec that have been carried forward seemingly unchanged from at least 1995. First two images are of the "TrueType Open" specification 1.66[1], the last is of the current OpenType 1.9 spec[2]. Notably the PDF of the old spec was generated from a document called ttch01.doc, which is also the last part of the OpenType URL.

[1]: http://hackipedia.org/browse.cgi/File%20formats/OpenType%20font%20format/TrueType%201%2e0%20Font%20Files%20Technical%20Specification%20v1%2e66%20%281995%2d08%29 
[2]: https://learn.microsoft.com/en-us/typography/opentype/spec/ttch01

https://cdn.masto.host/mastodondecentralisedsocial/media_attachments/files/111/067/550/214/934/396/original/f3d8a7c82577fff7.png

https://cdn.masto.host/mastodondecentralisedsocial/media_attachments/files/111/067/550/712/824/480/original/a6aa52de35e2eb02.png

https://cdn.masto.host/mastodondecentralisedsocial/media_attachments/files/111/067/551/093/694/047/original/422d76bbffe77df5.png