Over at A Neighborhood of Infinity, Dan Piponi has a post about a little bit of magic that happens when you ask gcc to do a division by 7.
This would have nothing to do with visualization aside from the realization I had in the shower, just the other day, that I believe the right way to pick good numbers for an axis scale is to think about the problem in the p-adic sense. “Small”, in this case, means pretty much exactly “close to a round number”. The usual descriptions of the algorithms (at least as I remember them!) for coming up with a good set of axis markings are pretty nasty; maybe p-adic numbers can help.