This very early rugmaking leaflet from Patons shows methods using thick rug wool in alternate holes, in every hole and describes an adaptation using thinner wool (splitting the wool into strands) using every hole of the canvas. It also describes a non-tufted method using "leviathan stitch". Leviathan stitch (Smyrna cross stitch, Railway stitch) combines a normal X-orientation cross stitch with an upright +-orientation cross stitch worked on top of it, creating a neat square (over a 9-hole square section) with a raised centre. See Flickr where they can be downloaded at full resolution for your own use.