Epicycloid

An epicycloid is kind of like when you play with a toy car and you make it go around and around while turning the steering wheel. But instead of a car, we have a point that moves around in a circle while our circle is moving around another circle. This creates a cool shape that goes in and out like a roller coaster. When we draw this shape on a piece of paper, it looks like a beautiful pattern that we can color in. Some people like to study these shapes because they helped us make gears and machines that help us do work more easily. So, an epicycloid is like a fun toy that helps us work better.