1. I chopped up old corrugated cardboard boxes with a paper cutter, and offered kids either square or rectangular shapes. They began by rubbing the board with the side of a black crayon.
2. A small amount of white tempera paint was rubbed all over the surface with paper towels. No brushes allowed to keep edges fuzzy and blended.
3. A small amount of black tempera paint was rubbed all around the edges of the board. The board was rubbed more with paper towel until it was dry to the touch.
4. Masking tape (1″ wide) was torn down the middle and applied to the board to make block letters. If I did this over again, I would have stocked up on a lot more red tape as I love how that pops off the board more than the others. Could be a good way to make signs for a haunted house or a school festival.