구글 클래스룸
GeoGebra지오지브라 클래스룸

origami

Don't get confused my the multitude of lines, just look at the green and red ones. I try to prove with geometry and/or algebra what's shown here: https://youtu.be/zU9FORjUnj0 Also, thanks James Grime and Daniel Hubbard, for the nice puzzle!