Love those socks, especially the bottom ones.
Magic needle is knitting on a circular needle that is too long for the size of the garment you are making so you do it in a loop. Hmmm that doesn't even make sense to me and I know what I'm talking about. I'll copy the bit out of my sock book.
"Use a circular needle with a sturdy cable and a length of at least 30 inches. stitches are knitted from one end of the needle onto the other end while maintaining a loop of cable between one half of the stitches and the other half."
If that still doesn't make sense, there are several videos on Youtube about it.