Extreme 2-in-1 Socks by Kory Stamper

Extreme 2-in-1 Socks

Fingering (14 wpi) ?
Double-Knit Stockinette
350 - 450 yards (320 - 411 m)
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This pattern is available for free.

The article for this pattern in Knitty is written such that it can be adapted to any gauge.  This is not so much a pattern as it is a tutorial for the technique of double knitting 2 socks at the same time, so adapt it at will.

ETA: There are a number of variations on the technique (including instructions for a flap-and-gusset heel and toe-up socks) at harmlessdrudge.com.