This is a little something I was doing. In this project, the purple rectangle rotates about the center point, and the 2 smaller colored circles rotate along with it. I've managed to figure out how the smaller circles can stay inside the rectangle whilst moving in a circular direction. I definitely might have to put this into use someday...
To prove that the smaller circles are aligned in the center of the drawing in the costume editor, their positions will change each time the green flag is clicked, and their arrows will change direction from left to right depending on their x position.