As Christine rightly points out, this is probably a Spiegelunion Flabeg copy, a West German company, of the Lace pattern originally designed by Chance (actually it was originally a photo from a piece of Belgian lace).
However, since I wrote the book there is another possibility: VEB Glaswerk Olbernhau, an East German company that is known to have copied the Swirl pattern (as did Spiegelunion as well). So it is a rather grey area as to who the producers are, but it is certain that this is not by Chance.
All will be revealed in Chance Additions - thanks for the (subtle
) reminder, Christine...!