Trefoiling: A triangular tile-and-pathway connecting game

A trefoil is an over-and-under closed 'loop' or knot. The Wikipedia article on Trefoil knot explains that: 'The trefoil knot is the simplest example of a nontrivial knot. The trefoil can be obtained by joining together the two loose ends of a common overhand knot [also known as a 'thumb knot'], resulting in a knotted loop'.