When do triangles tile by reflections? - The Ross Program

What happens if you take a triangle, and repeatedly reflect the triangle across its edges? Sometimes the result is a tiling of the plane.

[@NoNTr1v1aL]

Did you just teach me about reflection groups? Wonderful video by the way!

[@kisonecat]

I really love Coxeter groups!

[@jimgu2578]

I have learned the exact same problem in an advanced math class in high school. I only remembered when you transformed the question into a^(-1)+b^(-1)+c^(-1)=1/2.

[@kisonecat]

It is a fun problem, and very accessible!

[@IustinThe_Human]

the (3,12,12) triangle can constructed using the 30,60,90 triangle by reflecting over the shorter side

[@kisonecat]

That is true! Many of the other triangles are related too, e.g., (5,5,10) is related to (4,5,20).

[@andy_hay]

Awesome video!

[@kisonecat]

Thanks!

[@math_lover5292]

Wow!! Thats the beauty of mathematics.....

[@kisonecat]

It is really neat to see the triangles unfolding!