Chrissy writes in the book:

“When designing socks, I like to use unusual stitch patterns that showcase the yarn in unique ways. These socks began with my idea to use a slip-stitch pattern in which a horizontal strand of yarn is lifted a few rows later to make a little “tent” design. I placed this motif at the center of the pattern, then added a mock cable slip-stitch motif on each side. The mock cables complement the center motif and are worked over the same number of rounds for ease of knitting.”

--Copyright, Interweave 2011