You wake up in an empty room with only 2 doors. Each door has a key-hole where you can peek through. Door A is guarded by a dragon that will incinerate anyone it sees. Door B is simply a hallway, with an odd ceiling, it’s the strongest magnifying glass on earth! It magnifies the sun so strong it’ll burn you to a crisp the second you leave.
How do you escape?
Solution
Wait until night and walk across the hallway from door B.