I think this is what you are asking for. Could you go with 9" square? ..... But because you have specified 10", the numbers are not "pretty" lol. It is based on a 9 Patch so 10 divided by 3 is 3.333333" finished which when you add in the 1/4" seam allowance gets ugly. Here are the EQ cutting directions for a 10 " finished block