Reuleaux polygons (wheels, sewer lids, coins, etc.)

thingiverse

Create sewer covers and unique coins using Reuleaux polygons, an interesting shape boasting constant width. This feature makes them ideal for sewer cover use as they won't narrow enough to pass through the hole they cover. Reuleaux polygons are featured in British 20 and 50 pence coins, Mauritian 10 rupee coins, and Jordanian quarter and half dinars. Discover more about these fascinating shapes on Wikipedia under 'Curve of Constant Width' and 'Reuleaux Triangle'. This topic came to mind after seeing the 5 Shekel coin, a non-Reuleaux polygon coin. Note that although Wankel engines use a similar shape, it isn't a Reuleaux triangle due to slight differences in side structure, optimized for combustion ratio rather than constant width. For your own OpenSCAD programs, download the reuleaux.scad program and utilize the reuleaux_polygon(n,w) module, ensuring n is a positive, odd integer of 3 or more, and w represents the constant width.