# Cellular Automata Tea Cozy

I came up with this after reading part way into A New Kind of Science by Stephen Wolfram. Getting a knitting pattern out of it made me feel a little less ripped off.

It's baggy on top, for my housemate's 4-cup teapot.

## You will need:

• Red Heart brand worsted weight acrylic yarn, "royal" and "aran"
• Pair of #6 (4mm) circular needles, plus a set of double ended ones
• 80-bit pseudo-random seed, such as the des key for your favorite afs cell.
• Crochet hook, darning needle, etc.
• Sharp sewing needle and cotton thread

## Directions:

1. Cast on 80 stitches using double strand method.
2. Make a loop, and knit around four rows (since this is shorter than either needle, you'll need to use both, switching off appropriately). Add a marker and purl the fifth row, then knit one more.
3. Take 80-bit seed, put it in binary notation, and declare the zeros to be white. Holding the white yarn in one hand and the blue in the other knit the seed pattern.
4. For all rows onward, which color to use depends on the three stitches below it. It's easier if you make this decision before you pull the stitch you just knitted off the left needle, when you've got the three stitches in a row. This pattern is:
 000 -> 0 001 -> 1 010 -> 1 011 -> 1 100 -> 1 101 -> 0 110 -> 0 111 -> 0
which is rule 30 in Wolfram's notation (binary 11110, reading up from the bottom of my list).

If it looks like you'll be stuck with one color for a while, twist the two threads around each other on the back, so the loop isn't too messy.

5. Work in this manner for some reasonable distance. When you decide to narrow it for the top, you will knit two together, every ten stitches, or eight times around. Place a marker so you know where the row ends.

Each time you knit two together, since the decrease will slant to the right, the first of the two stitches you knit will not count in the pattern. Get a headache trying to keep track of this. Decrease in this manner, with the decreases on every other row, lining up with each other, for a while.

6. Get fed up with decreasing so slowly, and start to decrease on every row. Switch to four small needles at some point.
7. When you get down to eight stitches pass both loose ends through all eight stitches and tie them off.
8. Pick an area lining up with one of the decreases, and with a sharp needle and sewing thread do a row of backstitching on either side of a vertical row, being sure to catch all the ends on the underside, and repeating each stitch a couple of times in each spot. Make sure to catch a stitch at the top and bottom, too.

Wish for a sewing machine.

9. Take a deep breath, and carefully snip down the middle of the row of stitches.
10. Crochet a row of single crochet around the opening, using the blue yarn. Hope that all the fluffy bits are hidden. End with a slip stitch into your first stitch, and darn in both ends.
11. Fold the bottom in along the line of purled stitches, and sew it down, using the darning needle and blue yarn. Sew into a row of bumps on the underside, mostly ignoring the bigger loops from the other color not being in use.
12. Wish for some elastic to put into the hem.
13. Decide that this was a horrible idea, and resolve to do fold-over ribbing along the bottom, next time.