This project uses disposable camera lenses to create a 3D-printed stereoscopic lens, and a tilt lens that both share the same e-mount adapter. The lenses can be focused via a push-pull mechanism, and can be switched out without un-mounting the e-mount adapter. So you can just print one e-mount adapter and get two lenses!
Images taken with the stereoscopic lens can be converted to a video that shifts between the frames, creating a 3D-like illusion.
Below are the first test shots taken with these lenses: