Featured Old embroidered black and white textile - Swedish? Russian?

It is just a bit on how they embroider mostly black on white, using a frame (the usual type consisting of two rings, which seems to be a novel idea to the writer).
It is embroidery though, not weaving. The designs are more typical of Mexico, and a mix of indigenous and colonial.

 

Similar in design, and black and white, but different technique. These are typical cross-stitch. It is so hard when you can't handle a piece, and see front and back. I am leaning more toward eastern Europe for Bookahtoo's.

 

I finally found a good example of what is meant by supplemental warp. The base fabric continues underneath, but there are additional threads that are set up on the loom, and incorporated during the weaving process to create the design. Note on this example (as in Bookahtoo's cloth) the design/supplemental threads are heavier than the base fabric threads, and the design is reversed on the front and back of the cloth:


https://simplelooms.weebly.com/supplementary-warp.html
The link explains the process. I believe the technique is less common than supplemental wefts. It is not embroidery.