间

Why does 间 look like this?

门 (door/gate) + 日 (sun). Originally, the character showed the 'moon' (月) through the crack of a 'door' (门), representing a gap. Later, it was simplified to show the 'sun' (日) shining through the doorway. It beautifully illustrates the idea of a space, a gap, or the time between two points.