If you want to stick with your Greek theme, you have them design temple
facades. They could pick a Greek god or make up their own "Greek" god with a
myth. The artwork can be wall plaque relief sculptures made of bread dough-
edible or not. One really easy inedible recipe is 4 parts flour, 1 part salt,
and 1+ part water. Mix it up and knead it til it is workable. This gets baked
at 350 for about an hour. You have to keep in in the fridge to save for later
work because it will grow moldy.