Dot optic / thumbprint glass vases or bowls - Maker?

Does anyone have any idea who might have done these? The first two are mine, the last is from a recent eBay auction. All three have very similar bases, and roughly ground rims.

The first one I found several years ago, and asked about on the eBay P&G forum. It is a black amethyst color - a strange choice for an optic pattern like this. No one had any guesses at that time:



I recently purchased this orange / amberina one at a local flea market. It is almost exactly the same size as the black amethyst one:



And I stole the photos of this last example from a recent eBay auction. The glass on these is a lighter amethyst, which better shows off the thumbprint pattern. The overall diameter of these vases is smaller than mine, due to the "bookend" shape. But if you look at the base, you can see that the inner ring and line features from the mold appear to be the same, and roughly the same size.



Any ideas? Thanks!

 

Don't know about source but the effect (optic) once was called Polka Dot, dot, thumbprint and IVT (Inverted Thumbprint,) are made up names.

Its wondrous what words have been used for glass technology by students, my favorite is "Insuflated" used to indicate mold blown.

 

The Amethyst ones are Book Ends.

 

Thanks Tom and Fenton.

My apologies if this winds up being a duplicate - I typed a reply without being logged in, but it seems to have disappeared.

I did a revised eBay search for these items, and I found a found a few more examples in different colors and sizes. I also found some similar items with Japan import labels. I'm starting to wonder if these also might be imports, given the rough-ground edge, etc. They're nice looking for what they are, but certainly not elegant or high-end glassware.

Here are the other eBay examples, in case seeing them in other colors / shapes might jog anyone's memory:

Green: http://www.ebay.com/itm/Round-Green...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

Amethyst: http://www.ebay.com/itm/Amethyest-P...144?pt=LH_DefaultDomain_0&hash=item20ef1ebf48

Aqua (Bookends): http://www.ebay.com/itm/Two-Vintage...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

Blue (Smaller): http://www.ebay.com/itm/Vintage-4-I...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557