Multiple exposures defined as a a frame of the negative being exposed twice or more to create a single photograph, but sometimes you forget to wind the film and press the shutter again, a surprise will come out after you develop the film.
Multiple exposures is the easiest tricks can made in your photo by analogue cameras.
The simplest way is focus the object and stay firm, press the shutter for couples of times, then the object you focus will be multiplied in a single photos.
Next is using the back light effect to produce multiple exposures. Use your hands or other object which is big enough and have special outline, face it to the sun and capture once. At the same time, remember don’t wind the film. The first exposure of the object will become black and the surrounding will be white or blue (sky color). Then use the same exposure to focus on another object which has brilliant color like flower, tiles, etc.
Last trick is using the unique design of the building or other tall object to create multiple shots. Expose the first image as usual with your camera, then upside down ( opposite site of the exposed image) your camera, press the shutter, it will becomes two or more buildings in a single shots.