Example: http://www.cl.ly/2B062I2t2k210i0W1m0f
Sonic is over Einstein on the left, but under on the right.
When we move the first rectangle too fast towards the top, some of the events might get missed and the corresponding rectangle doesn't _exactly_ mimic the first one. As no more events are fired, it gets stuck.
You might want to introduce some sort of sanity check for when a rectangle exits the wormhole.
Fast movements definitely mess it up, with things not lining up properly, or being completely duplicated.
Even slow movements often leave the last few rows of Einstein hanging off the top of the Right side.
A really neat idea, though!
To me, and I think everyone else who regularly uses OOP, method names are meant to be verbs -- this would be a predicate, testing whether or not the object is a wormhole.
