There was an art dream.

The dreamer went back to a time when Tahi http://www.gambiacastle.net/tahi.htm was at art school. The Tahi in the dream had illusions. One consistent illusion occured on a white wall with a white noticeboard on it. Everytime he walked past it he saw this Hungarian shelf thing made out of recycled board, which had a green bucket hanging off the bottom shelf, which was supposed to be a compost toilet. Eventually he decided to make it so that everyone else who walks past the wall will have the same illusion.