Connecting threads has a free pattern that looks similar to yours. Whirring pinwheels or something like that.
I also have a quilt that I inherited when my mother died. I know she never quilted...never owned a quilt either. Comforters were the only things in the house she bought as she made all our clothes, bedding, curtains, drapery, apholstery, etc.
I have to take a pic of it, and put it on here. But no one knows where it came from. It just showed up in my mom's room at the nursing home one day. No label, no nothing.
This is exactly why quilts need to be documented.
M