I made about 100 of the Styrofoam balls this year for Christmas. Putting all those pins in was hard on the finger tips but everyone loved them. The tree is done the same way. You can do it with Easter eggs as well. I don't remember what it was called but I found some balls similar to the Styrofoam balls and they were much easier to push pins in and didn't make that horrible sound when you pushed in the pins.