Post some marbles which look like they could be made by more than one company.
A couple of Peltish Marble Kings:
My single-seam bumble bee:
Rainbo-y translucent one from early 2000's (I think)
How they're made sounds the same. How they look is different.
That's all I got.
(This is my way of thanking you for the thread and bumping even though I got nuthin.)
Would be fun for people to pose marbles from different makers in a way which shows of the ends of the streams.
"Were their mechanisms designed to keep shear marks as non-visible as possible?"
I'm going to guess that this wasn't a point of concern.
Thanks for the pix. Always a good time for Master pix.
However, the bag in this patent has cardboard on the back. Part of Israel's idea was that the cardboard support could also be used for advertising.
https://www.google.com/patents/US2085365
First picture -- two Tiger Eyes .... and the green and white and clear marble might be Akro. I don't know a Vitro name for it.
Second picture. I think all three of those are Tiger Eyes. The pattern on the one on the right is a little nonstandard but I think still Tiger Eye.
Third picture -- I think Akro on the blue and white. I don't know what blue with a little orange ring would be called. Is it a Bull's Eye variant? Not sure on the marble on the right.