That's another thought I had. The lack of exactness was making me a little nervous :)

Pattern on the left of what? Do you mean your avatar? Or in Amma's post? Or my original one? Sorry, got lost

Thank you!

Oh oh oh!! That's genius. I never thought of it as a snowball block. Thank you!

*blush* Thank you ... though I'd still opt for the tube technique ... faster, easier, and more accurate results!

You are very welcome :) :) :)

I think paper piecing would be the easiest and most accurate.

Here is a "math teacher" suggestion for using your requirement of the charm square aspect: sew two charm squares together on the diagonal a la HST-style; press to set the seam and trim leaving a 1/4" seam allowance. Next, draw a line where you want the parallel seam. Now, using the desired "trim triangle", position it along that line, right sides together, so that when stitched it will complete the square.
Note: the "trim triangle" will be a bit larger than needed so you could be "approximate" in placing it, if you are willing to square up the piece after adding that triangle. There should be a minimum of trim waste and the second "trim triangle" can be saved to be used in another project. Actually, all of the "extra" triangles could be sewn together to make HSTs.

It looks to me like the four quares are half square triangles with a snowball in one corner. Then the four squares are sewn together. Appears to be pretty simple. Cute idea.

I saw a video on this block..and now I can not find it. They used 2 -- 2.5 inch strips and 1 -- 1.5 inch strip. Sewed the entire length together, then did the traingle cuts on the strips. She showed where you can put the 1.5 inch strip at the end or the middle and how each way looked. I thought I saved the tute... nope.. one of my brain fart moments I guess.