A Leraud triangle rotates between parallel lines without changing the distance

Because Reuleaux triangles can rotate between parallel lines without changing their distance,they can work as wheels,provided a little creative engineering.And if you rotate one while rolling its midpoint in a nearly circular path,its perimeter traces out a square with rounded corners,allowing triangular drill bits to carve out square holes.Any polygon with an odd number of sides can be used to generate a curve of constant width using the same method we applied earlier,though there are many others that aren't made in this way.