This section is from the "Hand Sewing Lessons" book, by Sarah Ewell Krolik. Also available from Amazon: Hand Sewing Lessons: A Graded Course For Schools And For The Home.
Two pieces of checked gingham: 5 inches square; 4 inches square.
Cut from the center of the first a 2 inch square, clip the corners of the opening on the bias, fold back the edges to a color line in the gingham, fold back the edges of the second piece to match, baste one side at a time, and overhand. Trim and overcast the raw edges of the patch and of the opening.
Illustration 26. Cloth prepared for Models 17 and 18.
Illustration 27. Overhanded patch.
Illustration 25. Slash of placket, clipped before sewing.