Pedestrians become artists The China Environmental Protection Foundation placed street-wide canvases of a leafless tree across seven main streets in Shanghai(later expanded to v32 roads across 15 cities in China). Sponge cushions soaked In green washable paint were placed on each side of the road crossing and as pedestrians walked, their footprints created the effect of leaves growing on the bare trees on the canvases. The message is simple: see how much greener the would be if we all walked.