I've had so many letters requesting information about that popular folded patchwork technique called "cathedral windows" that I think it's time to give you the step-by-step instructions. There are many, many different ways of using this lovely pattern, which looks just like its name. Try making variations by interchanging light and dark and printed and plain fabrics for the folded squares and the background "windows." The fascinating three-dimensional effect is excellent for small things such as eyeglass cases, pin cushions and pillows as well as for large quilts.
To begin: Determine the finished size you want the window square to be and cut your fabric square four times as large. (For instance, for a two-inch square, you will need a fabric square of eight inches.) Make a square cardboard or sandpaper template pattern (eight inches square is a convenient size). Trace around the pattern on the straight grain of the fabric and cut it out with half-inch turnbacks all around. Press the turnbacks to the wrong side of the fabric square. Fold the square in half, wrong sides facing, and blindstitch or oversew each edge together halfway along.
Next, pull the long, open edge apart so that the stitching edges meet in the center. Now, from the center, blindstitch the two remaining open edges together halfway to the corners. Be sure not to sew through to the back of the fabric.
Turn the square over so that the smooth side is toward you and, one by one, fold the four corners into the center. Stitch all four flaps firmly together in the center, being careful not to catch the back of the fabric.
Make a second folded square in exactly the same way as the first, then join the two squares by holding the flat sides together and blindstitching the edges.
Now make the "windows" -- the little contrasting square of fabric which fits in between each of the joined squares. Cut a three-inch square of material, press a half-inch square of material, press a half-inch turnback to the wrong side of the fabric and position it in the center diamond formed by joining the two squares. To secure it, tuck it under the sides of the original turned-back corners. Roll over one edge of the original turned-back corner fabric on top of the contrasting fabric and hem it down. For more of a three-dimensional effect, catch each of the four corners together with a few stitches, instead of hemming. The finished double squares can be joined together in any arrangement to form the pattern you wish.