The reason for the formation of small ice flowers on the window: in cold winter, the temperature difference between indoor and outdoor is large, and the water vapor with high indoor temperature condenses directly into solid when it is cold on the inner surface of the door and window glass, forming ice flowers, while the water vapor with low outdoor temperature is not easy to condense into the shape of ice flowers on the outer surface of the glass: ice flowers are changed from small ice crystals, and ice molecules are mostly hexagonal, so ice flowers are mostly hexagonal.