On the Creative Challenge group we had to use a polystyrene tray in our work.
My theme is North American Indians and I had a drawing of Anasazi pots that I did for the last challenge so drew some patterns from that and carved them out of the polystyrene.
This was great fun in itself.
I then used them as stamps and used various paints to stamp them to paper and pre-painted fabrics. Here are some some of the results.