The reflection on the inside of the dome pointing downward. It's around 12 noon.

You’re studying at the Sheikh Lotf Allah Mosque. You want to know the time but the sheik is thundering from the mehrab. And by the way, it’s the 15th-century Iran.

The solution: just look up, at the spectacular hand-painted dome towering 30 meters above.

Iranian architects used the side windows to reflect the sun’s position into the dome, forming a long band of reflected light that serves as the hour-hand of a clock.