I Just Don't Understand

[Crunchygoblin]

I'm wondering if someone could make a small room with a door that opens when you walk into a the corner. And then send a download link.
Feel free to add anything else you feel would be beneficial to learning.
just make sure you state what you've done.

I've tried to figure this out, but i've have no luck. So im hoping i might be able to understand by see how its done.

Thanks!