Metal cages filled with rocks can be a brilliant material for construction. For instance in the famous Dominius Winery by Herzog & De Meuron in Napa Valley is a prime example of the tectonic qualities of the material. The only thing is: the material looks heavy and "earthy". In that respect, the Accesso Parque Metropolitan Sur (Metropolitan Park Entrance) by Antonio Polidura and Pablo Talhouk in Chile is a surprise. The materials are used for a strong shaped building, with a spectacular cantilever. I don't know too much about it, to be honest (since my Spanish isn't that good that I can read info about it), but I think the images speak for themselves in this case. Gorgeous stuff.