LandArt2014 asks the artists to find their raw materials in the adjacent forest itself. Then the art goes through the transitional cycles of time and decomposition. Some of the 14 entries had already merged with the forest. Others were still visible. I liked the one above by a team from France.
Pascal Imhof has produced an HD Virtual Reality of the French entry–and from this link you can see VRs of all LandArt2014 entries.