Quote Originally Posted by Caradoc
Interesting. I'd understood the one on the left as "pleating to the line," and the one on the right as "pleating to the sett."

I don't recall having seen "pleated to the tartan" before.
It makes sense though. The tartan is the pattern and pleating to set maintains the pattern, thus pleating to tartan. It's just not the term commmonly used.