Every year as our school prepares to open, they pull down dozens of stained
ceiling tiles. I like to break these into random shapes and plaster the
front(or have the kids plaster them). Kids draw on the plaster, then paint
with watercolors. The lines that show up in the plaster(hand plastering)
are like the random shapes that show up in the walls. They work around
these shapes, incorporating them into the work as some cave art used curves
to become bellies and horns on the walls.