With half a lens cap and double exposures you can get some really fun results.
You take a bit of card, draw a circle around your lens, and cut out half a circle, wit some extra spikey things to fold. Next you cut a strip of card and form it into a ring that fits snugly around your lens. About the depth or a regular lens cap, that should do it. Tape the half circle to the ring. Add some extra bling if you like. Result:
Now it's time to take some pictures. You'll need a camera without a shutter safety, meaning one you can do double exposures with. A Diana Mini, Holga, Yashica-D, etc. The basics: put the splitzer on your lens, covering the bottom half of the lens, and take a picture. Don't advance the film. Turn the splitzer so that it covers the top half of the lens, and take another picture. Now advance.
Of course, there are endless variantions, combining images, more than two exposures, covering more or less of your lens, etc. One of my favorite techniques:
- Cover the bottom half of the lens and take a picture of a bunch of slowers or a characteristic building.
- Cover the top half of the lens, turn the camera around 180 degrees.
- Take the same picture again.
The result is often surprisingly good.