This is such a great quilt, I've drafted a template. I hope you don't mind if I share it here. The dimensions are different from Angelia's (I drew it up in Word, and just made it to fit the page), but the effect should be the same.
Directions:
Assembly is similar to foundation paper piecing.
1. Place a black triangle in the centre triangle, making sure it extends at least 1/4" beyond the marked line.
2. Fill in the sides with dark and light strings, as indicated. The outer solid lines are to square up the block; the inner dotted lines are your stitching lines to the join blocks, accounting for seam allowances.