Homemade tilt shift effect question - something in front of lens?

Silly question but, is there anything I can put in front of the lens to create this effect (weird glass? Etc) I have a camera with a fixed/non removable lens (Leica q2) and want to experiment with tilt-shift in camera as opposed to on post. I realize I can achieve this in photoshop but I’d love to try something more organic and not afraid to get creative.