a tangle is a toy https://www.tangletoys.com/products/Details.aspx?p=995&c=106&g=all
One day I was playing with a tangle while sitting at a table and realized that I could take it apart to vary the number of segments. Then I noticed that is was possible to form coplaner shapes only if the number of segments was a multiple of 4. Then it became my goal to enumerate every possible shape for n=4,8,12.... once that became impossible to do by hand, the tangle programs were born