up a dark and a light square right sides together and all edges
aligned. On the back side of the top square lightly mark the
diagonal. Next, carefully sew a scant 1/4" away
from the marked diagonal on each side of it. After you
have done this cut apart on the solid lines, between your stitching..
Each square pair will give you two half squares. Press them to the
darker side, and trim to measure 3-1/2" if needed. You need a
total of sixteen half squares...