yup --double knitting..
wait, make that 2 color Jacquard type double knitting (since there are lots of sorts of double knitting..
including 3 color (2 different patterns on each side of the work!) jacquard double knitting..
I've blogged about it..
its great for
reversible garments (i've made a vest, but scarves and hat and blankets are popular)
pot holders (double layers make them more insulating.. a single layer knit potholder isn't going to protect you from burns!)
place mats, and other household items (bath mats!)
there are other types of double knitting
2 color 'shaker (aka Brioche stitch) double knitting, or simple double knitting :
cast on even number of stitches, every row:
K1, bring yarn forward, as if to purl, k1, bring yarn back as if to knit. (repeat across row)
in the book Knitting new scarves.. there are scarves that are made by
X rows of ribbing (1 X 1 ribbing) that then changes into X rows of simple double knitting (to make stocking knit on both sides with a 'pocket' between the layers, back to ribbing..
Very interesting, very different, and fun!