1. I glued the basic square as shown ahead of time for the young students to keep things sturdy. Give each student white glue and enough sticks to fill in the box as shown to make a flat board.
2. Collect a bunch of small items (like buttons, paper clips, puzzle pieces, etc.) that have different shapes and textures and have the students glue them down with generous amounts of white glue. Let dry overnight.
3. Paint everything heavily with white or black acrylic paint. It make take two coats to block out all the underlying color, which is the goal.