Cathedral Windows quilts aren't, strictly, quilts. There isn't the 3-layer fabric and batting "sandwich" that is the standard definition of "quilt". The pattern is based on folding squares of fabric. The folded squares are whipstitched together, and then small colorful squares are appliquéd over the joins, inside gracefully turned curves.
I like to think of the process as being very similar to the folded paper fortune tellers my friends and I made ad infinitum when we were 8 or 9 years old. Does anyone else remember recess on sunny afternoons, choosing numbers and colors, and then getting a funny fortune? Over and over and over?
Anyhow, I've been repairing a lovely Cathedral Windows quilt. What makes it particularly beautiful is the choice of fabrics that fill the little "windows." Very often, the quilts are made with multi-colored calico scraps. This quilt's windows are all filled with color wash fabrics in rose and blue.
The effect is lovely, like rippled pieces of colored glass, or maybe like the flicker of sunlight coming through trees outside the windows.
The reason this quilt came to me for help, is that on the back, the little flaps are coming unstitched.
....... Wait a minute ....... Flaps on the back?
I couldn't remember ever seeing a Cathedral Windows quilt with this problem before. It took me a while to figure out why this problem seemed so strange.
I finally realized, after making some paper samples, that the woman who made this quilt made the folded squares just like folding those paper fortune tellers. Those are made by the folding corners of a square to the middle, flipping, and doing that again. The thing is, when making Cathedral Windows, the fabric square shouldn't be flipped. Then all the little corners end up safely inside the blocks.

#4 left, Cathedral Window, smooth back / right, fortune teller, flaps on back

#1 first fold, corners to centers
#2 left, no flip, for Cathedral Window/ right, flip, for fortune teller
#3 left, second folds
left, flaps inside, Cathedral Window / right, smooth inside, fortune teller

#4 left, Cathedral Window, smooth back / right, fortune teller, flaps on back

So, I've done loads of sewing on the plain white back, but every now and then, just to make me happy, I flip it over and enjoy the sun pouring through the lovely stained glass.