The children are sharing the popcorn, puting the pieces of popcorn into their bowls which are on the floor. The boy takes the last piece.
Two small mice come out from under the couch. One mouse puts a sign displaying 50 percent by the boy's bowl and the other puts an identical sign by the girl's bowl. They then scurry off while the sleeping cat opens one eye.
Adapted with permission from web accessibility pages at Penn State.