Well, math has never been a strong point and today I am baffled. I am making a simple block 12 1/2" and am going to do half square triangles, but cannot figure out the size of the squares, everything I am reading or watching on u tube has muddles my after christmas burnt out brain. Can anyone tell me how big the squares have to be? Please. I am attaching a pic from EQ7 of the finished 12 1/2 block. Thanks so much.