Thanks Jan. That is a very good illustration. I just finished doing that with 13 blocks. Yes, you can put 13 blocks into a quilt if you put them on point.
I cut my triangles a little larger, too. (Much better too big than even a little too small.) Then I took my ruler and measured from point to point and cut the edge off at 1/2 inch from the points. After putting on the border, my blocks "floated" by 1/4 inch. It looks wonderful. Better a float than a chopped off point.