ELI5: Explain Like I'm 5

Hypersphere

A hypersphere is like a shape that looks like a ball, but instead of being flat like a circle or round like a ball you play with, it is round in more than three dimensions. Imagine a regular ball, like a basketball. Now, imagine that instead of just going around the ball, you can also go in and out of it, like running from one end to the other. But, instead of just being able to do that, you can do it in any direction you want, without any limits. That's a hypersphere. It's really big and it stretches out in ways that we can't see because they go beyond our three-dimensional world. Scientists use hypermathematics to study them, and they help us understand things like the universe and how particles move around.