Unusual WWI Panorama Photo - circa 1920

Three positives and one negative, 12x3.5", b&w. The negative is so long that the positives were pieced together at the left fence line, apparently because the photo paper was too short. Subject is a line of six DH-4's and maybe DH-9's in a line on a grass field. I have never encountered such a format with the assumed date of just post WWI. Very good. The price is for all four items.