Spiral Baby Rib Hat                 

Hat measures about 14" around and will fit a small baby. 

See below for how to adapt for other sizes.

I used Baby Weight/Sport Weight Yarn - about 50g

Size 7 dpns or a long size 7 circular needle if you are using Magic Loop method

Gauge - 5 sts = 1"

Cast on 72 sts and join into circle.
Work 12 rounds in k2/p2 ribbing.

Work in spiral rib patt as follows:
Rounds 1-3: (k3 p3) 12 times
Rounds 4-6: p1 (k3 p3) 11 times, k3 p2
Rounds 5-9: p2 (k3 p3) 11 times, k3 p1
Rounds 10-12: p3 (k3 p3) 11 times, k3
Rounds 13-15: k1 p3 (k3 p3) 11 times, k2
Rounds 16-18: k2 p3 (k3 p3) 11 times, k1
Repeat these 18 rounds once

Shape top:
R1 (k3 p1 p2 tog) 12 times
R2 (k3 p2) 12 times
R3 (k3 p2tog) 12 times
R4 knit
R5 (k2 k2tog) 12 times
R6 (k1 k2tog) 12 times
R7 (k2tog) 12 times **
R8 (k2tog) 6 times
R9 (k2tog) 3 times
Work I-cord on remaining sts - I did about 2" then finished it off and tied a knot in it.
** If you don't want the I-cord you can stop at this point, draw up the remaining sts and finish off.  You can find instructions for I-cord below. 

To adapt for other sizes:
The pattern is in a multiple of 6, so you can adapt this to bigger (or smaller) sizes easily.
Cast on as many as you need and work the body as long as you want.

Variation
2-color version
Instead of k3 p3, work * k3 color A, k3 color B*.

Making I-Cord:

You will need two of an appropriate size of double-pointed needles.

Abbreviations:

K = Knit
Sl 1 = Slip one st knitwise
PSSO = Pass slipped stitch over

Method:

Cast on 3, 4, 5 or 6 sts using double pointed needles.  Or in the case of this hat, use the stitches remaining after you decrease to the top of the hat.

Knit, don't turn.

Slip the sts back to the beginning of the needle and k the row again.

Continue in this manner until you have a short length of knitting, pull down on the cord and the gap at the back will close.

Continue until the cord is the length you desire.

Thread the yarn through the sts and pull firmly. thread it through a few stitches on the back of the hat before cutting.