Now Try This
Admire your work! We hope that through the exercises in these first three chapters, you've gained a new respect for the Solid layer in After Effects. If you use these ideas and techniques as a jumping-off point, there's no limit to what you can do with solids. Let your imagination take you where it will. Here are a couple of options to get you going:
Replace every square of a particular color in the backgrounds with a video clip, to create a wall of televisions.
Use the vertical and horizontal flips as dominoes to spell words or create an image or shape.