The discussion revolves around innovative concepts for constructing mechanical computers using various elements like spur-gear differentials and shishi-odoshi. The user expresses a desire to create distinct mechanical computing systems that utilize these mechanical devices to build basic logic gates such as NAND. The spur-gear differential can be used for its unique properties but requires careful engineering to function correctly. The shishi-odoshi presents a charming yet intricate challenge, as it necessitates interaction with water flow to achieve the desired logic functionality, highlighting both the complexity and the aesthetic appeal of such constructions. This approach embodies a blend of engineering and artistry, aiming for a 'Zen computer garden' aesthetic.