They're not hard at all and go together quite easily. Cut your triangles so the base is always on the straight of grain, then sew the rows so the bases are on the outside edges. Your finished rows will not stretch if you do that. Also be sure to press the seams of each row all in the same direction and alternate the direction in every other row. That will spin the seams where the points meet up as you join the rows. Take your time with the cutting because accuracy is really important with these layouts.
Here's mine. It's a strip pieced thousand pyramid layout of my own design (and a Hoffman Challenge finalist in 2009).
