Excuse me for patting myself on the back here but I just did my first successful double slit experiment. And it was easy! I poked 2 small holes in aluminum foil just as close as I could and shined my kid’s cheap red laser through them and Viola! I thought I needed razors and prisms and 2 lasers, but no. It took me about 5 minutes to get it right. Now I have to figure out how to get a detector by one of the holes.