Puzzle: A hospital has 16 rooms and each room has a different disease, the patient in room 13 can go through each room but if he goes through a room twice he gets their illness, how can he get out without going through the same room twice?
Answer: The correct answer is 13 → 14 → 13 → 9 → 10 → 11 → 15 → 16 → 12 → 8 → 7 → 6 → 5 → 1 → 2 → 3 → 4.
Room 13 is not allowed to enter other rooms more than once in the hospital. This means that the patient in room 13.