I am looking at an old Wilton book and one of cakes uses this technique but does not explain how to do this. I also can't find much about it (in relation to cake decorating) on the internet. Is it just using tip 1 and fill in your design w/ strings?
Moydear77 did a most incredible cake featuring a crewel piece. I'm thinking she used fondant for her's though. If I were to pipe one, I would first look up crewel work and follow the directions for it but with icing instead of thread. I've not seen it being done since I was like 6 y/o...isn't it like filled in in multiple directions? I can't remember. I'll try to hunt down some useful info for ya.