Multiplicity is the blending of multiple shots of the same scene with potatochop to – for example – make it seem like there are multiple losers in the same shot. Unless that problem was “what’s a cheap gimmick I can introduce into my photography”, it’s an answer to a problem nobody’s ever had. I know that getting multiple people to pose for your shot might actually require you to take a shower, but it’s worth it.
Back around 1990, my friends and I used the basis for this effect to do “special effects” – and I use that term liberally – with an Amiga and a Video Toaster. Yes, your gimmick is so old that nerds with blogs were using it 20 years ago. It has its uses, but unless you’re into special effects just leave it alone.