From a Catriona Shearer [url=https://twitter.com/Cshearer41/status/1125306444151230466]puzzle on twitter[/url]. [br][br]I got interested in the general structure. The original puzzle is to find the green angle when the radii are 3, 2 and 1. Super nice![br][br]Here you can set the radii in the 2nd option, or choose the tangent point on the first circle.