This isn't what I came here to write about, but while looking for an illustration, I found this photo in my Flickr stream. It's from a 2009 exhibit at the Royal Festival Hall in London, celebrating 150 years of Plasticene, I believe. The bust is of the great man William Harbutt who invented the non-drying modelling clay for his students.
All of those leaves, flowers, and bricks, the tree, the apples and the pathway are all made out of the modern product.
There was a vegetable garden:
and a half-eaten picnic, with scotch egg!:
It wasnt' there for long, but it was one of those things where there was just so much to look at, I probably spent an hour just examining closely all the little details.