Stack some scrappy squares. Cut them from corner to corner, twice, creating 4 triangles out of each square. Then mix them up so that you have 4 triangles from 4 different prints. Cut your sashing. Insert sashing between pairs of the triangles, then between the two sashed pair units. Square up your blocks. Set them with same size sashing between blocks and rows. Very simple.
eta: Oops, looks like several of us gave her the same answer.
