I came across this simulator while doing research for my Weekly Robotics project[1] and found it very satisfying to watch. If you'd like to learn more about the project then here is the link to the publication:
https://arxiv.org/abs/1909.03372 and a video:
https://www.youtube.com/watch?v=cwPaof0kKdM[1] https://weeklyrobotics.com/