Styrofoam Printing

I got some takeout food the other day in a styrofoam container, instead of throwing it away, I decided to make some printing plates from the foam. I just cut the Styrofoam into large flat pieces and carved into the foam with a ball point pen. Then I rolled acrylic paint over the top and then laid the paper over it and rubbed the back of the paper. I then lifted the print off. I should have added a little dish soap to the paint to help it adhere to the foam, it was fun any way.