Normally I slash a rectangle of fabric diagonally and insert a strip, then sew uprights on either side to make my N's, but that's a not very efficient if you're making twelve.
After a bit of thinking, I created sewed background fabric to either side of piece of orange fabric,
then cut 1-1/2" strips apart at a 45° angle, like this.
Then I sewed this piece to orange uprights, but....
I chopped off the corner of the angled piece, since I knew I would cut it away later.
Press them and then I'm done. W00t!
(Remember this letter is barely 3" square)