Ok, maybe I had to say veiligglas.
Yes, they usually have only one wire in a clear transparent base, (type 3) a single wire in a colored transparent base (type 2) and a two-color double wire (one almost always white) in a clear transparent base (type 1)
These are standard, but not really all came out in this way, some can have many filaments of this type, which yes, could fall into the swirl category, but always veiligglas, this is what I meant to say ...
The marble in question, both the swirl (although poor) as well as the glass, give me the impression of veiligglas,... this is just my impression, then ....