10 minutes to bedtime

With 10 minutes left before their bedtime (Ok, is actually one hour late) I decided to let them play for a while. What I did was to place all the pillows in the room and form them into a big soft mass. Then, I let the girls jump as much as they want but with some simple rules that they cannot jump if someone is still in the mass. Or, if the pillows break off, they must stop and then rearrange them back. And most importantly, they cannot aim their jump outside the mass........