You don't discuss strip piecing, which I have found makes construction of these blocks even easier. For me, sewing strips together and cutting rectangles is a lot faster and easier, especially when you are using alternate blocks. But, if you are doing a scrappy quilt, cutting individual squares of material is the only way to go.
I have enjoyed your tutorial and the pictures of the many ways to use 9 patch blocks. I had not seen the arrow block or the disappearing 9-patch block. I see a couple projects in the near future!