20210727 debugging

Quick sanity check for overlapping shapes and an initial state residing within limits.

• Turn off gravity. Nothing should move when you play.
  • If something does move..
    • Disable collisions on everything
    • If something still does move..
      1. Disable all limits and guides
      2. Enable limits one-by-one
    • If something now does not move..
      1. Everything is OK
  • If something does not move..
    1. Everything is OK