Multiplicity is achieved when several photos are taken of a model, either a human, an animal or an object in the same frame, and then in Photoshop the images are layered and edited to create one photo which combines all the photos.
I used a tripod to take these photos, however in Photoshop I soon realised that at some point my camera had moved slightly, which made the photo hard to edit as some parts of the scene didn't match up, like the brick lines and I also noticed that some of the photos had different colours, which is due to the natural light changing.