The I-cord is a tube knitted in the round with two double-pointed needles. Elizabeth Zimmermann named it the Idiot Cord in honor of her accidental discovery of the simple technique. The I-cord is a perfect example of her attitude toward knitting: let it be fun, free of needless complications, and full of discovery. In this picture from The Opinionated Knitter, a wonderful collection of her newsletters, Elizabeth wears an I-cord attached to her glasses. Once you learn to make one, you'll be searching around for anything that might be improved with an I-cord.
Cast On and Knit
To begin, cast on 3 stitches onto one of your double-pointed needles. Knit these 3 stitches normally, from the left needle to the right.
Now all 3 stitches are on the right hand needle and the yarn is attached to the left stitch. Slide the stitches from one end of the needle to the other like this:
The Trick of It
Without turning the needle, place the needle in your left hand. The yarn is coming from the far left stitch. Pulling the yarn so that it is snug, knit the 3 stitches from the left to the right needle. Everything is normal EXCEPT the yarn is coming from the last stitch in the row instead of the first when you begin knitting this row.
When you have knit all 3 stitches onto the right needle, slide the stitches from one end of the double-pointed needle to the other. Repeat these steps, pulling the yarn snug at the beginning of each row to insure even stitches. Bind off normally.