1. Due to it’s openings it sheds light and allows air into the interior of the house. Worth mentioning fact is that in the past the Tinians were into sericulture and the worms needed both fresh air and light!
2. The arched shape of the hyperthyron offers relief to the stone wall structure.
3. It is often decorated with various designs that deter the evil spirits away from the house. That is also why they were placed on top of the most “vulnerable” points, the doors and windows.