I darned a sock yesterday using a different method (Cookie A’s). Here is the hole in the heel: Here’s what it looks like from the outside after the repair:I used a different yarn to darn. The original yarn had no nylon; the repair yarn does. And here’s what it looks like from the inside: This technique is very interesting. The patch is partly new knitting and partly duplicate stitch (on the edges). I will report back about its effectiveness at a future date!