Why Is The Shape Of A Shadow Always A Circle?

Shadows are like cookie cutters for light. Imagine the sun is a giant lamp shining down on you, when it shines straight, your shadow stretches out and becomes long. But if something blocks that light in a round way, like a ball or a moon, your shadow always looks round because it’s just copying the shape of the thing blocking the light. It's like drawing with a circle stamp every time.