It would actually be pretty funny if the extraterrestrial technology we like to imagine taking the form of some geometrically-perfect prism of exotic nano-mater

It would actually be pretty funny if the extraterrestrial technology we like to imagine taking the form of some geometrically-perfect prism of exotic nano-materials did indeed exist, but had to be enclosed, for entirely practical reasons, in plain old riveted stainless steel. It wouldn't even be that far off from what our species does anyway, putting our advanced nano-materials (integrated circuits) inside cases made of much lower-tech materials. All that said, I don't think aliens would have left the lid behind.