One string in each of the following pairs can be unraveled into a circle—the so-called unknot. Which one is it?
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!
The top right knot is equivalent to knot 2, and the bottom left one is equivalent to knot 4.
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