2 exposures in a single frame

2 exposures in a single frame. Two portraits of the same boy, wearing shirt and short on both photos. On the left picture, the boy is standing on a pedestal table, and has sandals. On the right photo, he is sitting cross-legged on the pedestal table. No backdrop. Date of original material: [1953-54]. Size of original print/negative: 3 ½ x 2 ½ inches (2B). Format of original material: Glass plate black and white negative.