If you are inclined to join in, but haven't yet, let me know. It's not too late. :)
cut one square 7 1/4" from the background fabric
cut in half on the diagonal twice, forming 4 quarter square triangles
cut 4 squares 3 1/2" from the background fabric
cut 4 squares 3 7/8" from a medium print
cut 4 squares 3 7/8" from a dark print
cut only 2 of each of these in half on the diagonal once
to make:
4 half square triangles from the medium print and
4 half square triangles from the dark print
mark a diagonal line on the back of the 2 remaining medium print squares (to prepare to make triangles)
take the 2 remaining dark and 2 remaining medium 3 7/8" squares and layer them together, right sides together.
sew a quarter inch seam on either side of the diagonal line, cut apart on the pencil line, press open
to make 4 squares
layout as shown
sew together and square up the block to measure 12.5".
I'll try to answer any questions in the comments.