From the Stitch Description: This pattern has nearly as much lateral stretch as a ribbing. It is quite fascinating when left entirely unblocked, so that the vertical ribs can close up together except where they are pushed apart by the purled welts. This produces a series of highly embossed waves that look almost as if they were done with the aid of a cable needle.

Location of Stitch: Page 18 from A Treasury of Knitting Patterns.