By Aki Inomata, quite literally taking the hermit crabs ability for carrying their home on their back, the Japanese artist crafts architecturally inspired shells from plastic for the crabs, with miniature cities on them. I think another fantastic aspect is the transparency, how you can see the anatomy of the crab even when they withdraw is just fascinating.
The use of negative space on shapes and letterform can achieve great results showing two concepts or ideas at the same time. Here are great examples of typographic logos showing hidden shapes between his forms and letters. You can see the whole set here: bit.ly/1cCXGGU