This took some concentration. I frogged it early on, and tinked many times. I used my new favorite technique for garter stitch edges:
Beginning of row: Knit 1 tbl. Last stitch of row: Bring yarn to front, then slip last stitch as if to purl.

Texture makes it look square, rather than diagonal. Straight needles work better than circular for dishcloths, for me.

Obviously, I made some mistakes. I’ll know better next time. Nobody chose this as TOPS incentive, so I gave it to DD’s MIL.