As hermit crabs grow, they require larger shells. Since suitable intact shells are sometimes a limited resource, vigorous competition often occurs among hermit crabs for shells. Japanese artist Aki Inomata, sympathizing with those forced out of their homes by larger crabs, sought to help them find a new home with her series titled "Why Not Hand Over a "Shelter" to Hermit Crabs?" Using 3D printing technology, she studied the natural shapes of hermit crab shells and printed out new "shelters" that the hermit crabs would move into (if they chose to). Their crystalline-like shells are shaped like tiny magical castles, houses, and other structures modeled after cities from all over the world.