A 2 ply gimp. One ply is twice as fat as the other–40 and 20 wpi, roughly.
I’m still experimenting with constructions in Sarah Anderson’s The Spinners Book of Yarn Designs. I’d like to try this one again, but skinner, for socks.
The fiber is Hello Yarn Still Life on BFL. I stripped out all the navy and used it for the skinny ply. Ravelry Spinning deets are here.