An interative/simulation inspired by an awesome video by 3Blue1Brown.
Just came across some good work by github user asa55, which involved, refining and simplying the code used in this project. Please refer to that version if you want to use the framework and the code used in this project. And, also check out the other projects there.
When special relativistic equations for elastic collisions were taken into account, the constant energy curve isn't an ellipse at speeds close to the speed of light. It's more of a rounded rectangle.