Harriet, dear, remember you're talking to a non-quilter.
I thought I was doing well last night to understand how the folding and seaming work for this block, and accepting that it uses extra fabric in the interest of saving time. Now you're talking about borders and math and
Although ... I understand what you say about staggering the Cathedral Window placement. I think that would be interesting in a table runner.
I like that this block can be made from any size starting square, since I will be limiting my quilting projects to wall hangings, table runners, and placemats.
If we get enough fabric donations for our Quilts of Valor community sewing event in September, this would be a quick way to make up a lot of blocks.
There is another youtube video for the same designer's 5 Minute Block. (Suzanne McNeill) She shows how different ways of setting the blocks will create a wide variety of designs that look really complicated but are in fact easy to stitch. Those could also make stunning Quilts of Valor, and they would look unique even if all used the same set of fabrics.