Create Your Own Sliderule

There's a neat article in Scientific American's May issue about the history of slipsticks. You can download a template and make your own. I realized that you could make one without knowing about logs. If you take a two rulers, label the left edge '1', and then each regular tick mark with ascending powers of a number, e.g. 2, 4, 8, 16, 32, 64, you can multply the numbers just by adding lengths--a primitive slide rule. To add other numbers, you'd have to do the same with powers of 3, 5, 7, etc. and be able to shrink or expand the scales in order to reconcile where the numbers properly go. For example, 3 squared is 9, which should be greater than 2 to the 3, but less than 2 to the 4.