Chugging away at my Twisted socks, I idly glanced through the pattern, something I have not done since casting on. (Uh-oh)
The abbreviations list caught my eye--specifically "Slp." Slip stitch purlwise? But... that's what I've been doing all along, when instructed to Sl1!
I'm so used to following patterns that assign the abbreviation Sl to slip purlwise that I automatically started slipping my stitches this way on these socks. Completely missing the whole "twisted" part of this slip stitch rib. Whoops. In fact, there's a bit in the pattern notes that specifically says Sl means slip knitwise... but since I only looked at the pattern to see how many stitches to cast on, I didn't notice. My bad.
What you see here is a regular, untwisted slip stitch rib, created by slipping the knit stitchs purlwise every other row. Pretty, but not what this pattern intended. I briefly considered leaving it and continuing in my nontwisty rib for the rest of the socks, since it looks okay. Ultimately, I think I like it better twisted, so I think I'll rip back and actually follow the pattern. (Deliberate disregard for pattern instructions is all fine and good, but since I chose this pattern because I liked it as written, I'm going to stick with it.) Sigh. Commence frogging!