I like the gobletty thing.
Have you looked carefully
inside the pieces, on the bottom?
I've got a fabby fish jug in purple slag glass (thank you DavidE.
) - it's full of metal staples holding it together, making it doubly fascinating.
On th bottom, inside it, I can just about make out a diamond shaped mark, with a large R in the middle. The corners are marked out into sections with curves and there is a semi-circular shape on the top.
The section on the left has an "L" in it, there's the number 24 in the top inside bit, and I cannot make out what is in any of the other sections.