I cut up a notch in the top of a roll of expired 35mm and then in the dark, unrolled it to the end, then taped it to a marker cap, rerolled it and jammed it into my square format childhood camera, a Kodak Instamatic X-35F. I knew it would leak but I wanted it to some, but I did tape one side that I was able to to see obvious light through. After each shot, I twice wound the camera and fired off the shutter with the lens held against my arm. This was necessary to have the film advance enough to not overlap too much. I didn't know what it would do so I shot a few of the same scene.