Here is my square 11. This was done on size 5 needles, and came out to the right width with the given number of stitches to cast on. I only did 70-something rows, though - not the 82 it called for.
Halfway through I realized that it doesn't specify how to slip you stitches, and I was slipping "purl-wise" on both right and wrong sides. Then I switched to slipping "knit-wise" on the right and "purl-wise" on the wrong sides. I don't think it looks much different, though.
(It was easier for some reason)
We're all a little tired of the mosaics, so we're going to jump to S17 and then come back to S12. However, by the looks of it, the slip stitch ones don't appear to be much different than the mosaics.