Lay out your 4 squares in the pattern you want. Place the top row right square over onto the top row left square, right sides together. Fold your 5th square in half. Lay it between these 2 pieces lining up all the edges at the bottom and the short edge of the 5th square on the right edge. Pin.
Now, place the bottom row left square over the bottom row right square. Open up the first pair of squares and insert the other short edge of the folded 5th square between those 2 pieces. Pin. You should have a funny-looking mess with one square of each fabric on the top of both stacks & the alternate fabric on the bottoms. Now stitch and press.