This a secondary illustration that went into the Fudebakudo book, to illustrate a lengthy bogus text about a rare book from the late 15th century: Borogove’s “Systematic Anatomie of Man, his Life, and Contrivance for Ending It”. It was one of a few places where faking diagrams up was more appropriate than using a cartoon, because sometimes the illustration needed to be more “plausible” for the joke to work (this is actually Photoshopped from a woodcut from Vesalius’s “De humani corporis fabrica").
Some people did catch on that everywhere this nonsense was going on, Fudebakudo was taking its names from Lewis Carol’s wonderful Jabberwocky.
Many years later, I was astonished and embarrassed to discover that this particular visual gag had been subconsciously inspired by the master of martial arts parody, Robert W. Smith (writing as John F. Gilbey): as a teenager I’d seen something very similar in one of his books and didn’t realise until about fifteen years after Fudebakudo’s publication (so, over 35 years after seeing Smith’s diagram) how closely I had regurgitated it. Significantly, at the time I had totally failed to realise that his one was deliberately fake. I suspect that he would have loved to know, and I’m sorry I found out too late to tell him.