Block D-13
I think Jane may have done a lot of her designing by folding paper and then drawing in the lines. She may have cut her block apart and then used if for her templates.
I'm attaching D-13 as an example - it matches the drawing, but when I look more closely at the photograph, the center does not come out to the edge like the drawing does. I may or may not change my pattern.
The dotted lines represent the fold lines. The solid lines represent the design lines.
If Jane just traced around the pieces, she could have used any size square and not have to worry about making it easy to measure.
There are quite a few blocks in the quilt that seem to have this shape as part of the design.