Hermit crabs search for suitable houses once they outgrow their old ones, and when suitable snail shells aren't available, they settle down for whatever they can find that's vaguely shell-like. Some are lucky enough to find something strong and serviceable and cute, but most of them live in crap. This and other similar projects might not solve the problem (shell exploitation for all purposes is a large industry; hermit crabs are the only customers that would settle for a plastic alternative but they need more than a bunch of hobbyists with printers can make), but it's a noble sentiment, I guess. As a side note: the house doesn't have to be snail-shell-shaped on the outside, as long as it's comfortably crab-ass-shaped on the inside; the houses can be ornate or funny shaped like that teapot example, they can look like tiny brick houses or Volkswagen Beetles or camper vans or footballs, crabs don't mind. Imagine an aquarium full of crawling Advance Wars tanks So if you have a suggestion or design on your mind, send a comment to the MakerBot team.