One string in each of the following pairs can be unraveled into a circle—the so-called unknot. Which one is it?
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The knots at the top left and the bottom right can be unraveled into circles:
Challenge problem: The other two knots, which can’t be completely unraveled, can each be made to look like one of the four most basic knots. Identify them!
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The top right knot is equivalent to knot 2, and the bottom left one is equivalent to knot 4.
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