Nottingham lace curtain stitches

This week I’ve been trying to study the various stitches used by the Nottingham lace curtain machine and understand how they are made. I now have a better idea but still have much more to learn. There seem to be two main types of ground stitch: filet and Swiss net. The filet grounds produce a square net like handmade filet net and they can be single-tied or double-tied at each side, depending on whether the bobbin thread linking the warp and bottom board thread together passes round them once or twice. In Swiss ground the net is not an exact square but forms a V shape, which you can see in the image above. There are then many variations depending on whether every bottom board thread is linked to the adjacent warp, linked to the warp beyond that one, or just twisted round the warp to form a pillar. It is complicated but I am beginning to understand it!