These V-Houses were designed by Heinz Legler for use as eco-friendly shelters. They are in temporary use for workers is a forest near Yelapa, Mexico, but have proved so popular that more have been ordered to house resort guests. They feature solar panels, composting toilets, and a greywater system to reuse as much water as possible. No excavation needed to set these treehouses up, just stick them in the ground! Link -via Digg