This is a game/activity that I made up when I was doing daycare. The kids always love doing it. You hand each child a piece of paper and they draw one thing, then pass it to the next person and that person adds one thing to that and you keep going until all the papers are full. The only rule is you cannot ruin something someone has already made, like cross it off. (if you play with boys, this rule must be enforced) You can also make another rule if you'd like, like only one color on that one thing, or only one part, like if you pick to draw a flower, you can only draw the stem and then pass it. But usually we just play with the one rule of not ruining something already done and each person can draw one whole thing each time.
The middle picture was the one I started and I thought it would be a house, I drew the frame of a house, then Mary drew a line (pole) going down from it, she thought it was a birdhouse. So the picture changes according to the next persons' vision.