Next, we fixed the following objects just inside each entryway with silicon: 1. A dish smeared with sticky hair gel. 2. A swatch of soft furry material, the kind they use to make stuffed animals. No, we did not sacrifice any child's toy, we just happened to have the piece handy by chance; 3. A strip of rough sandpaper from the hardware store.4. A thin toothpick, held up by skewering a paper cup with it and gluing the cup to the box.5. A round plastic ball.6. A hard stone. Who knows where my daughter got it from.7. A cold gel pack, the kind you use to take care of bruises or sprains.8. And finally we covered the last door with transparent cellophane to simulate the sensation of pressure.