The location arithmetic board was a strange instrument invented by John Napier, published in 1617, used to multiply binary numbers. The theory of binary numbers didn't exist at the time, so Napier invented that too. (kinda)
Here is a short video about the location arithmetic board:
Napier's book includes a fold-out page with a 22x22 location arithmetic board, capable of giving answers up to 247 = 140737488355328. I don't know of any super-high quality scans of the original, but below is a vector-based PDF which can be scaled up to any size.
I am releasing these into the public domain: anyone has my permission to do whatever you want with them. If you want to buy a nice big printed version, I will get a few bones if you buy it at my shop here:
