Christine, isn't that peloton? I know it isn't raised threads off the surface, but I thought it was done in the same way, just that the threads are flush with the base colour (or in this case, cased in clear so covered and smooth and also flush with the base colour perhaps)?
I have a modern piece that is done in the same way, I love it. But yours looks old? It looks to me as though it should have a little lid sitting in there and be a jam pot.
m