Weaving a Circle

I tried tapestry weaving for the first time last year. The design included a circle, which turned out to be challenging. The project was so difficult, I thought it had better be turned into something useful. It is going to be a pillow cover, once the back (made from mosaic-knitted strips) is complete.

Mosaic knitting could be pieced to form a pillow back. Strip on the left is blocked; grey one in the center will be the same size upon completion.