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If you hold a mirror up to one trefoil knot and look at its reflection, what you see in the mirror is the other trefoil knot! The two trefoil knots are called mirror images of each other.
The two trefoil knots are different, but not all knots are different from their mirror image:
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The figure-8 knot, for instance, is the mirror image of itself.
One way to classify knots is according to whether the mirror image of the knot is the same knot or a different one. Can you classify the knots from the sheet of knot diagrams this way?
