This caused copious confusion for new players, who assume the
glass "tank" is like an aquarium tank and can be used to carry
water. Originally it was intended to seal in "moisture" for
sponge transport, but that has become a far less important use
case (and in fact sponge transport is probably best done just by
building submerged pathways, like the way amalgam transport is
done) and glass "tanks" are more like "display cases" now, or an
intermediate storage container that adds top access (useful for
totes).
This makes glassmaking more challenging, as glass that is quenched
when not molded, or left wandering too long, will tend to quench to
crude glass, which is inferior.
This also prevents molten glass from wandering the countryside
forever from failed glassmaking attempts, and precludes keeping
molten glass in "captivity" as a crude infinite light source.
It should now be possible to obtain the new optical stuff given
only resources in-game. The molten glass casting process, in
particular, should be at least a little interesing.
These recipes aren't very interesting and may be subject to
refinements in the future.
