From My Pieced Alphabet:
The triangles can be sewn using the connector corner method - place squares over the corners of the rectangles, sew them on the diagonal, fold them back, and then cut off the excess on the back of the letter leaving 1/4" seams.
As a result, points, like the one circled, need to be reasonably precise.
This is a heavy alphabet. The detail of diagonals that just touch give it some finesse.
For more alphabets go to My Post by Subject in the sidebar on the right and click on Lettering