I can't seem to find any instructions for square hemstitching. I would really like to give it a try

Hi Carla, I’m not sure what you mean by square hemstitching. Have you done a Google search? There are a couple of books you might be able to find in the library - one that I like is Finishing Techniques for the Handweaver by Virginia M. West.

I saw it in a post somewhere down the rabbit hole. It has little squares on one side of the fabric and Xs on the other side.