I found out how to make a bag of popcorn in sandbox mode. This is actually a glitch though. First go to sandbox mode and draw a hollowed out big box with a very tiny opening at the top of the box. Make sure the box is pretty big. Then hold space and start clicking randomly in the box. This should produce many circles on spaces and sizes. If you do it enough it should glitch and the circles overlap on top of each other and vibrate violently kinda like popcorn (:
I think we should be able to decide when to end the level because when I destroy a city there is still a lot of money left over on the ground and I lose a lot of it because it doesn't give me enough time to pick it up at the end.