- A 1920s proposal for a telescope-based “optical internet” was recalled: libraries would use arrays of mirrors and mechanical switches to transmit microfiche images over line-of-sight optical links, predating digital networks.  
- Participants searched for a primary source documenting this scheme but could not locate it; the discussion was sparked by a link to 2015 IRC logs where the idea was first mentioned.  
- Pneumatic data networks were noted as an even older precedent, although the conversation distinguished the optical microfiche concept from conventional pneumatic-tube systems.  
- A 2011 paper on subterranean communication infrastructures (Steenson, “Interfacing Subterranean”) was shared as potentially related background reading, but it did not contain the sought reference.