Once upon a time, when trees, houses and dogs were very large, all toys were created with simple things.
If you put an arc on a cube, you can make a swing. If you put a triangle and a cross on the swing, you will have friends on the playground. If you put crosses, circles and an arc - you will get a funny, sad or sly face. If you put an arc on another arc and set up all the pieces on it imagine how much can come of it.