This photograph was taken of Chewbacca and C-3PO as they prepare to shoot a scene in The Empire Strikes Back. There are quite a few interesting abnormalities that litter the photo here and there.
One of which is the mop and broom that are still in the corridor they are about to shoot down. Another is the peculiar wooden prop that the crew is using to aid them in the scene. It has a bunch of peculiar jutting and strangely angled wooden beams. Chewbacca seems to be gripping onto one of said beams in an attempt to pull it along.
The contraption’s purpose appears to be able to help them with shooting C-3PO in this scene as just a torso. It helped keep Anthony Daniels’ legs down and made them easy to edit out for the final cut.