Metabolic Architecture or Metabolism is the design principle covering these capsule hotels or similar accommodation pods. What's interesting about them is that these buildings try to mimic organic biological growth. Here's the world's first example of Capsule Architecture, still originating from Japan.
Nakagin Capsule Tower in Tokyo | Source
Great post @afterglow!
Thank you. That Nakagin Capsule architecture still look futuristic even if it is very old.