Closed circle

Imagine you have a drawing of a circle. Now, imagine that you start at any point on the circle and walk all the way around it until you get back to where you started. The circle is now said to be closed because you made it all the way around and ended up at the same point you started from. It's like walking in a circle and ending up back where you began. A closed circle has no beginning or end, and it always stays the same size and shape. It's like a delicious cookie that you can eat forever without ever running out!