Napier's bones (Napier's Rods)

Ludwik Fleck's "Genesis and development of a scientific fact" goes very much in the line of looking at science as a gradual progress, with many failed attempts. written by winners. (Written pre-WW2; it served as an inspiration for Khun.) Its most eye-opening example is the history of [the concept/knowledge/science/... of] syphilis, from ancient to modern times. PDF (of print from 1979): http://www.evolocus.com/Textbooks/Fleck1979.pdf

I actually just saw these for the first time on Sunday at the Computer History Museum in Mountain View.

The main attraction was the final cranking of Babbages Difference Engine No.2 Serial 2, that thing is gorgeous in operation.

I had an awesome math teacher in 3rd grade that taught us how to make these out of popsicle sticks and use them.

I always wondered why stuff like this never catches on in a school's math curriculum. Perhaps it's viewed as a gimmick that is impractical in the real world?