A torus link
Three untied circumpherences are an example of torus knot of type (3,0). If we want to get a torus knot of type (3,k), we can take three line segments drawn on a cylinder and roll up the cylinder to for a "doughnut" after having imparted a twist of a particular angle (k times 120°). The image shows the case k=0; if we give a complete twist, we obtain the torus knot (3,3).
See also the interactive animation Two numbers for a knot.
immagine di Gian Marco Todesco