Verlet Integration

Inspired by this series:
https://youtu.be/3HjO_RGIjCU

You might want to turn the gravity up if it is running slowly for you (Press 'g')

Press space to start/pause the simulation
While paused you can:
- click on the stage to create points
- click the points to connect them to each other
- shift-click points to anchor them
- click points/sticks while pressing x to delete them

Press +/- to show/hide some options