Many years ago (20?) I bought 'Knitting in the Nordic Tradition' and have been intrigued ever since by the following quote in it (from Leo Tolstoy's War and Peace) and accompanying comment about the mystery of knitting two socks simultaneously:
" 'Ann Makarovna has finished her stocking,' said Countess Marya. 'Oh, I'm going to have a look at them,' said Pierre... Pierre went into the children ... 'Now, Anna Makarovna,' cried Pierre's voice ... 'when I say three you stand here ... Now, one, two, three!' 'Two, two!' cried the children.
They meant the two stockings, which, by a secret known only to her, Anna Makarovna used to knit on her needles at once. She always made a solemn ceremony of pulling one stocking out of the other in the presence of the children when the pair was finished."
"The maid's pattern is still a secret. How Anna separates the two stockings is still uncertain. the quotation makes one wonder how many knitting details and fine points have been lost during the years."
And then yesterday I came across this. How exciting! Mystery solved! : two socks in one