9 Rosette line patterns

[arca_libraria]

I think these are called "diapers" ...

Yes. Diaper is a really common decorative motif and/or space-filler across lots of different types of medieval material culture. It was used for decorative stone and wood carving in buildings and on furniture, as well as a pattern-filler in manuscripts. I’m not sure if I’ve ever seen it on embroidery or pottery, but that might be because I haven’t looked! It’s common as a single band and also as a chessboard-style space filler as well.