Two stitches make everything
Every knitted thing, from a plain SCARF to a patterned SWEATER, is built from just two stitches. The KNIT stitch pulls a LOOP of YARN through from the back; the PURL stitch pulls it through from the front, and looks like a little bump. They are the same movement done in opposite directions, like the ones and zeros of computer code.
Combine them and the fabric changes. Alternate a row of knit and a row of purl and it lies flat. Alternate them in columns — two knit, two purl — and you get RIBBING, the stretchy bands at cuffs and necks that hug a wrist. Cross a few stitches over each other and you get a CABLE, the twisted rope design on thick jumpers. A PATTERN is written in a shorthand that looks like a code: K2, P2, repeat.
Swatches, tension and a matching gauge
Two people knitting the same pattern with the same WOOL can end up with jumpers of different sizes, because everybody pulls the yarn a little more tightly or loosely. That is TENSION, and knitters measure it by knitting a small square first and counting how many stitches fit into ten centimetres. The GAUGE printed on a pattern tells you what count to aim for, and the fix for being off is to change NEEDLE size, not the way you knit.
Yarn is bought in a SKEIN or a ball, and its FIBRE matters as much as its colour: wool is warm and springy, cotton cool and heavy, and acrylic cheap and easy to wash. To start, you CAST stitches on to the needle, and at the end you cast them off so nothing unravels.
Knitting for soldiers
During the First World War knitting became a national effort in Britain, the United States and elsewhere. Charities sent out official patterns, and volunteers of all ages turned out millions of woollen socks, balaclavas and MITTENS for soldiers in cold, wet trenches, where dry feet could prevent trench foot. Schoolchildren knitted in class, and men knitted too.
Knitting was not always thought of as women's work. In medieval Europe the professional knitting guilds that made caps and stockings were made up of men, and fishermen in many coastal communities knitted their own thick, tightly worked sweaters, dense enough to keep out spray.
A hook, a spool and some mathematics
CROCHET is a cousin of knitting that uses a single HOOK instead of two needles, and works one live loop at a time, which makes it easy to form circles and three-dimensional shapes. In 1997 the mathematician Daina Taimina used crochet to make physical models of hyperbolic space, a curved geometry that mathematicians had struggled for more than a century to picture. Her ruffled models are still used in teaching.
A knitting SPOOL, or French knitting doll, is a small tube with four pegs on top that turns out a long knitted cord, and it is often a child's first way into the craft. The rest of the grid is the cosy results: the BEANIE, the SOCK, the BLANKET, and the STITCH that holds it all together.