Jan in VA - that is exactly what I needed to do....So I guess it is actually called a diamond in a square.
I did pick up some sandpaper and that was a great help in marking the diagonal sew line. After lots of trial and error, and with the help of my new best friend Seam Ripper, I did find the right spot to sew just off the line. Practice makes perfect....but it takes so very long, and sometimes I get a little impatient.
I think I have everything figured out for this project. All I have left to do is add a border.
You have all been so very helpful and I'm looking forward to my next project.
Dee