Thanks for sharing!
https://en.wikipedia.org/wiki/Arithmetic_billiards
With curved reflecting boundaries and parallel rays you get the beauty of catacaustics. A familiar site in a cup of coffee
https://en.wikipedia.org/wiki/Caustic_(mathematics)
Thanks for sharing!
https://en.wikipedia.org/wiki/Arithmetic_billiards
With curved reflecting boundaries and parallel rays you get the beauty of catacaustics. A familiar site in a cup of coffee
https://en.wikipedia.org/wiki/Caustic_(mathematics)