I've got a circular slide rule (not really a rule, is it?) with square and cube values, so you can convert surface and volume. Conversion numbers are printed on

I've got a circular slide rule (not really a rule, is it?) with square and cube values, so you can convert surface and volume. Conversion numbers are printed on the back. It seems to have been made as a cheap handout. Not that I ever use it, but it's a cool idea.