well… on the other hand: have been triangles ever experienced without a consciousness?

this "the idea of triangles would still exist" statement looks very reasonable, but can we ever proove it? you can not remove ALL consciousness to verify. at least a bit consciousness must be in the system to do the experiment.

yes, it very much coincides with all of our understanding of reality, that abstract ideas like triangluarity is independent from any consciousness. at least any consciousness known or conceivable to us so far.

so my extension to this statement would be - admittedly supernaturally-sounding - that: Even if all sentient life in the universe died out tomorrow, the idea of triangles (and "triangluarity") would still exist, possibly because there is a consciousness above/beyond of the conceivable the universe to sustain their existence.

We're very quickly coming to the realization that information is a physical quantity, like mass or energy. (And can be measured and follows some sort of physical laws.)

If so, then consciousness doesn't need to exist for information structures to exist.