Beyond the White Door

1. If by backwards you mean east is west and left is right then ...
2. ... you flipped the universe (changed its handedness) by your actions.
3. Specifically, by your movement.
4. You moved through the pergola loop, which is really a Klein bottle. (See previous question for details.)
5. Every time you completely move around the pergola loop, everything outside changes handedness.
6. This is mostly confusing, but it also comes in handy.