split vision

Oh, this is neat. Hold up a hand-mirror in front of your face, and then tilt it to the right or the left by about 45 degrees so that it reflects the things on that side of you. Then walk around (your house for example) holding it like that so that part of your vision is seeing the regular stuff and the other part is seeing the reflections.

If that isn't enough, bring the mirror right up against the tip of your nose so that one eye is completely seeing the reflections while the other eye isn't.