This simple program generates celtic knots using what is probably a standard algorithm. Touch the screen, or drag your finger around, to create knots galore.
Bob learnt the algorithm from Arnold Burdett, in a Royal Institution lecture. Many thanks Arnold!
v1.1.1: unfortunately the save/load functionality in GameMaker that we were using, no longer seems to work, so we've had to remove it from the app.
v1.1.0: random graphical glitches fixed.
v1.0.8: no changes at all from v1.0.7!
[Game Maker v1.3 now seems to generate apk's which are in violation of a part of Google Play's terms of service, so Bob recompiled the game using Game Maker 1.4]