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

From Mathologer.

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
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 ðŸ™‚

The winner of Marty and my book Putting Two and Two together is Alexander Svorre Jordan. Congratulations. ðŸ™‚ Thank you again to everybody who submitted an implementation of the dance. Here are five particularly noteworthy submissions:
(Kieran Clancy) https://kieranclancy.github.io/star-animation/ (this was the very first submission submitted in record time ðŸ™‚
(Liam Applebe) https://tiusic.com/magic_star_anim.html (an early submission that automatically does the whole dance for any choice of parameters)
(Pierre Lancien) https://lab.toxicode.fr/spirograph/ (with geared circles)
(Christopher Gallegos) https://gallegosaudio.com/MathologerStars (very slick interface)
(Matthew Arcus) https://www.shadertoy.com/view/7tKXWy (implements the fact that BOTH types of rotating polygons are parts of circles rolling around DIFFERENT large circles)

The animation in geogebra (by Juan Carlos Ponce Campuzano):
https://www.geogebra.org/m/tfqmub4g

The version of the animation I show in the video I stumbled across on Instagram, Twitter, etc.: https://tinyurl.com/36dy6nm3

The new book by Marty and me:
https://bookstore.ams.org/mbk-141

New short videos on Mathologer 2:

New Mathologer instagram account:
https://www.instagram.com/the_real_mathologer/

Spirograph:
https://en.wikipedia.org/wiki/Spirograph
(a nice app)
https://faishasj.github.io/spirograph/