Here is a very nice project that [Znaxque] finished a few months ago: a simple nixie clock made with logic gates only.

YouTuber Steve Mould has created a great demonstration of computer logic gates using water, tubes, and 3D printed components. This innovative approach provides a tangible and visual way to ...

From there, with some size reductions, a Master-Slave J-K Flip Flop, similarly using NAND gates and inverters, can be built. The current state of the project is a working sequencer and counter.

DNA logic gates calculate square root using 130 different molecules A DNA-based computer uses simple base-pairing to create AND and OR logic gates … ...

Researchers have reverse-engineered a cellular signal processing system and used it like a logic gate -- a simple computer -- to better understand what causes specific cells to migrate.