Trefoil Knot

A trefoil knot is obtained by joining the loose ends of an overhand knot. It is the simplest type of knot in knot theory and is the unique prime knot with three crossings (a prime knot is a knot which cannot be expressed as a sum of two other knots).

An interesting fact about the trefoil knot is that there is no way to transform (i.e., stretching or twisting) the picture above to one of its mirror image!

The trefoil knot pictured above was generated using the Matlab built-in demo knot.