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Breaking news: You probably have two eyes.
Ok, that's not news, and frankly, this isn't a breaking story either, but it is a neat trick you may want to try if you've got a piece of paper to hand.
Roll it up into a tube and look through it with one eye, as if a telescope, while placing your hand over your other eye, a couple of inches from your face.
If you look through the tube primarily, it will begin to look like there is a hole in your hand.
This is due to a thing called binocular rivalry - ie. your eyes competing for dominance in focus.
Watch the full explainer by Vanessa Hill, below:
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