The Video Game History Foundation did a video & accompanying article about Argonaut's relationship with Nintendo a few years back:
replyhttps://gamehistory.org/eclipse-the-demo-that-sold-3d-to-nin...
Based on that, I believe Giles is mistaken in the Eurogamer interview cited by Wikipedia. The demo was on Gameboy, not NES. The also-linked NintendoLife article also mentions the demo was on the Gameboy. But I guess maybe that's actually more impressive!
There was a NES and later SNES prototype (By Pete Warnes and Carl Graham) that was IIRC the focus of the 3D chip discussions. X was cool, and a good selling point (and predated the NES work), but there was (again IIRC) no interest on going further with 3D on GB.
Seeing custom hardware on carts (Pilot wings, Mario Kart?) and having dealt with the custom hardware on the Konix, gave Jez a good avenue to explore with Nintendo.
replyHadn't heard about that before. Argonaut and Nintendo also co-developed a 3D game called "X" on the Game Boy, that might give us an idea of how it could've looked.
replyI'm assuming they're referring to NESGlider, which became Starglider on the SNES. But I can't find anything but textual references to it.
replyThe 6502 can do wireframe and pseudo-3D. 3D has a lot of different types and levels, but prior to this there already wireframe and pseudo-3D products out there.
replyNESGlider was a wireframe demo. Of course very impressive technically but just a tech demo. The 6502 chip spent almost 100% of its processing power just calculating the 3D lines, leaving very little room for smooth gameplay or filled-in polygons.