Symplectic Geometry
《Symplectic Geometry》 · 第 2 页 · Section 1.1，Figure 1.2 中 granny knot 的连通和与原图
The overhand knot commonly used to tie string is called a trefoil. It comes in two mirror-image forms labelled left-handed and right-handed. Tying two overhand knots in succession produces either a granny knot or a reef knot, depending on which kinds of trefoils are used. […] granny knot \((3_1\#3_1)\).