For some purposes you can work even more simply - just printing the images on top of each other. In each area of the print the image with the least dense negative at that point will predominate. As so often in photography it depends on the effect you want, although here considerable experiment is likely to be called for. Since images build up on top of each other you will need to divide the exposure time between the images - and can experiment with different ratios. Interesting 'motion' effects can be made from a suitable single negative by moving the paper or enlarger head between or during exposures.
Similar logic applies to working in-camera with multiple exposures.
Working against a black background will give little or no exposure to these areas, so you can take several pictures with no change from normal exposure so long the images don't overlap. However, where the film will get exposed in the same areas from each exposure you need to divide the normal exposure time between the exposures. I searched high and low on the web for good examples of images created using these techniques. Except for those I've used in previous articles I couldn't find anything worth linking to. There are some examples, particularly of multiple exposure, but little that shows any planning or fulfilled intention.