Quote Originally Posted by Caradoc
I think the "evening plaid" has fallen into disuse for the most part, and what I see most of the time now is the "fly plaid," consisting of a piece of tartan dangling down the back from the brooch on the shoulder.

I've seen vendors carry "evening plaids" that look an awful lot like a "piper's plaid," but I think they're shorter in length such that the tapes fasten around the waist, then the plaid comes up to the shoulder, fastened with the brooch, and left to dangle down the back.

The "piper's plaid" wraps around the torso before being allowed to fall from the shoulder.
Caradoc explained it well. The fly plaid is gathered at one corner, run through the left epaulet and pinned at the breast with a brooch. It hangs loose sown the back.