Last one was somewhat complicated and easy to dismiss, so I've developed a more straightforward proof that I've realized.

Bendy light requires that what we perceive as a right angle is not quite a right angle.

The observer thinks the right angle is really not a right angle - but it is.

Therefore, all the angles we have ever seen are wrong.

Needless to say, a building like the

Burj Khalifa would never stand. In fact, I can't imagine much of any building that would stand, even a simple lean-to, if the lean is completely off. For any modern building, I'd say we'd have to be exactly right, or it would fall.

Therefore, we are exactly right, and light doesn't bend to make us wrong (otherwise all the buildings would collapse).

Therefore, bendy light is impossible.

Q.E.D.