bearisgray.... Sorry for the mistakes on my drawing.
Thank you so very much for the info regarding "starting with a 'finished' size where length and width are easily divided by the same number". Now I have something to work with. The White border will FINISH at 2 inches and I want this border to go around the top of the mattress about 2 inches in before the 3 sides overhang off the bed. I don't want "pillow" length, so there will only be 3 sides to overhang. Yes, I can place small borders around the center rectangle, or since I have started over, I can make the center triangle any of the dimensions you mentioned above. I do not have the expertise to make a star block without a pattern, the one I have in mind that finishes at 6 inches, then I need to place it on point. I have no idea what it will finish after I sew on the fabric that will make it on-point, sad, isn't it. Based on what you are explaining (teaching) I need to determine just what size the center rectangle will be, I am leaning towards 48X60 using 6 inch finished on-point blocks. I know I will have to place some type of border on the top and bottom so the white border won't look like a square, like you said.