Seems to have been a popular tile, did they produce many designs?
This is the only one I've seen so far. Who knows who made it or when-- "Sandwich" is one of those terms used fairly indiscriminantly. Presumably s'wich + early date hooked a bunch of people. My two Luxfer skylight tiles are the only two survivors from a trashed installation-- once again, the wrecking ball just pulverized it. That's why architectural glass is so much more scarce than decorative glass. They were recovered from a dumpster (tip)! Here it is:

The possibility of a totally glass house would seem to be realistic today.
You might be interested in Dr. Willem van der Heyden's all-glass house of 1891, built in Meiji, Japan. Pedro Guedes has written a paper about it. Before-its-time is stating it mildly.
About the object, it reminds me of a bulkhead light diffuser as used in ships etc to bring light (normally sunlight) to the interior of a hold or similar space. The modern version are those light tubes that smart designers are using for buildings. However as this item as a depression then maybe it was used with an artificial light source.
Hope this text is illuminative and not diffusing the matter further.
Deck prisms! Yes, predecessor to prism tiles, vault lights, etc. It's because I thought it might be a vault light that I bought it. But, does not appear to be so. It's not designed to be set in iron or concrete. So far I've seen
ONE original hexagonal deck prism on eBay, and I utterly blew the sniping (local computer clock wrong). I grieve every day for missing the opportunity. It
hurts!
The stropper is very interesting, thanks for that. Here's another type of glass I collect, often mis-identified (like this one):
GREEN DEPRESSION Glass REFRIGERATOR TRAY ESB Co RARENo, it's not kitchenware. Anyone care to hazard a guess? The #7 appears to be the most common size-- I already have two, so didn't pursue it.
My Hayward Bros hexagonal pavement light arrived from Canada today! My first H.B. light, and the one shown in their revolutionary patent application of 1871!
--ian