A couple weeks ago when they called me back to the lab the supervisor had one of the clear polymer disks on their desk that had formed in a pint sample bottle that was about half full.

The sample recycling operator came across the occasional one that had polymerized, over months of identical ambient storage to the other bottles in the case which could still be handled as liquids.

Broke it out of the bottle and brought it into the office, where it was completely odorless and sitting there like a promotional acrylic paperweight with nothing embedded inside to promote :)

If this tank has a giant disk of clear acrylic at the bottom, it "might" be unprecedented to remove it intact and turn it into a fairly sizable lens if possible. If not clear, maybe even a mirror of some kind anyway.

Although there is probably some internal piping from inside the tank, embedded for display purposes primarily at this point ;)