4" = 12 s
Cast on 4 s on US 11 needles with one strand of each of the two yarns. Knit garter while increasing on every row like this: Knit until you have two stitches left on the needle. Knit in the next stitch two times, in both the front and the back loop.
Increase until you have 24 stitches on the needle. Knit next row as follows: *K1, put 1 st on a second needle * until end of row.
Knit 1” over the stitches from both needles (separately, to make two flaps) Knit the 2 flaps together again by knitting 1 st from first needle and 1 st from second needle alternate until all sts are back on the same needle. You now have an opening to slip trough.
Continue in garter until desired length. Decrease like follows on each row: Knit until 3 stitches is left on the needle. K2tog. K last stitch. Decrease like this until you have 4 stitches left on the needle. Bind off. Weave in loose ends.