PRO/C / Projector and camara

In our childhood we liked to use color pen draw on the wall, but mommy always got angry. We didn't propose to make her angry. Is there a way to paint on the wall and easy to clean?
Yes, the PRO/C can. It combined projector and small cam. The cam can recognize the drawing pens' movement and the projector project the loops on the wall it projected. So you can draw any place, and use any color.
In that case, the drawing could be preserved and memorized in its computer. So your drawing won't be erased away. Further more, it can also memorize the baby's growth, and the pets', or the plants' you raise by drawing.