The 3-4-7 miracle. Why is this one not super famous?

I got sidetracked again by a puzzling little mathematical miracle. And, as usual, I could not help myself and just had to figure it out. Here is the result of my efforts. 00:00 Intro 08:45 The Coin rotation paradox 16:00 Mystery number explanation 18:38 Challenges and the new book 19:53 One-minute animation on how to figure the sum of the angles in a star 21:04 Thank you :) First entries for my coding challenge (amazing stuff. Must see :) (Kieran Clancy) (Richard Copley) (Liam Applebe) (Nan Ma) @nanma80/rotating-dots-along-star-polygons (Morten Barklund) (Chris du Plessis) Some helpful links. The animation in geogebra (by Juan Carlos Ponce Campuzano): The version of the animation I show in the video I stumbled across on Instagram, Twitter, etc.: https:/