There are small dioramas, and then there are these. They are teeny.
Using putty, plastic and a whole bunch of patience, a NicoNico user named "A" created miniature versions of Pallet Town from Pokémon Red, a Hyrule from The Legend of Zelda: Ocarina of Time and the Bob-omb Battlefield from Super Mario 64.
To give you an idea of scale, the Pallet Town diorama can fit on a 10 yen coin, which is about the size of an Australian 10c coin. One "dot" is 1mm.
This, of course, is Pallet Town.
And finally, this is Hyrule.