fool your freinds

first grab four toothpicks(works with pencils too)

then put them facing the 4 corners
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once you do that make them look like this= --
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now tell them to make a square with only moving one of those tooth picks/pencils

they wont be sure and if they try, set it back up as it was before
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then, you make the square and here is what it looks like: - -
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in other words all you have to do is move the thing on the right so then it will make a sly little square