- Left click to drag points (corners, joints etc).
- Press ctrl to enter/exit edit mode.
- Press "G" to switch gravity.
- Press "R" to remove traces.

When in edit mode:
- Click to add points.
- Right click to delete a point
- Press shift to unselect a point.
- Select any two points to join them.
- Click "F" and choose points to fix/unfix them.
- Click "P" and choose points to set/remove Pen.
- New points will join to the last point by default.


- based on
Physics Playground
JSVerlet