Hilbert curve knitting

My mother had a knitting machine that could make two-colour patterns controlled by punch cards. I thought it would be fun to have a jersey with a Hilbert space filling curve on it, but mum pointed out that the horizontal runs would leave long loops of wool on the reverse.

The machine had a second mode which its manual didn't explain properly, and the book she had bought to accompany the machine wasn't much better. I worked out that it was inverting the colour choice in a quincuncial pattern, and was able to make a punch card that looked nothing like the resulting Hilbert curve pattern. The reverse has no loops of wool, and no strong pattern.

The jersey lasted several years before moths got to it. I took this picture shortly before putting it in the recycling.