王偉仲、高欣欣  (from the left)

陳訓祥、陳榮凱、郭嘉真 (from the left)

陳訓祥、陳榮凱、Bianca Violet (from the left)

This is a detail of a pair of solid trefoil knots.

A trefoil knot is basically a closed curve - there are no ends to tie or untie - and it can be obtained by joining the two loose ends of a common overhand knot. You cannot untie it in three dimensions without cutting, which makes it a nontrivial knot. It is actually the simplest nontrivial knot.

The trefoil knot is named after the three-leaf clover (or trefoil).  There are two variants: the left-handed and the right-handed trefoil knot, and it is not possible to continuously deform one into the other. This property is called chirality.

In knot theory, the trefoil knot can be classified as a (2,3)-torus knot. It lies on the surface of an unknotted torus in three-dimensional Euclidean space, winding two times around the interior circle line of the torus and three times around its axis of rotational symmetry.

A solid trefoil knot is the boundary surface of a small smooth tubular neighborhood of the trefoil knot curve.

Find out more about how to create solid trefoil knots with the SURFER software here.