Because you never know what trivial bit of information may ultimately prove to be vitally important.
Reminds me of those glass block skylights for basement offices you can see in downtown sidewalks (at least in San Antonio; I assume other cities have them as well). Also, I understand ship builders used similar technology with quartz crystals (or something similar) in old sailing ships.
They're called deck prisms.
And here, I posted this, which is a picture I took a few years ago of the sidewalk skylights (though I'm not sure if that is the true term for them).
That is pretty damned clever, and sickeningly cheap too! Reusing the idea for deck prisms, and from my experience in Galveston on Elissa, they work with moonlight too, tho not as bright, obviously.