The evolution is really quite fascinating. At first, the swastika and penis faction was losing since it is easier to erase than draw, but then they figured out that you could make the work of the clean up people harder by stippling their drawings, so the erase tool became less effective. In response, the erasers began to draw over the drawings and were quickly pushed back by the erase tool now used by the villains. Now it's almost balanced with both factions using the stipple technique.