hy, that seems to be so nice i like it ... i was thinking, to make it a bit more interesting, because 'perfect' simetry is not beautifull ... sand dunes are not identical, being shaped by wind or sea waves ... use a random distorsion algorithm, so to generate an uneven field ( for example, google 'fisheye effect' ) , and layer it over a simetrical shape, maybe crop the final result, so to make the mind think about the rest, make the mind imagine what is missing / kindly