Make, learn and talk about needle lace.
Interesting question. I only recently became aware that Youghal uses only a single thread, not a doubled thread. I had thought that all the others used a doubled thread. Youghal is a 19th c invention, a late development. But I don't know nearly as much about needle lace history as I do about bobbin lace history. I suppose the way to find out would be to examine as many pieces of antique lace as possible, looking for cut ends where it might be possible to see.