Eskimo bowline structure of the knot was not identified by Clifford Ashley (in 1944). All of the maneuvers to tie this knot are generally in the opposite (or 'anti' direction) relative to the bowline. Dan Lehman regards the general, bowline-like structure as an 'anti-bowline' in the sense of "anti-clockwise": in that with regard to the main nipping loop, the tail on returning from forming the eye is brought through this loop in the opposite direction relative to what is done for a bowline. When this knot is ring-loaded – and the knot effectively becomes an end-to-end knot – it is effectively a
Arf invariant of a knot if they are related by a finite sequence of pass-moves, which are illustrated below: (no figure right now) Every knot is pass-equivalent to either the unknot or the trefoil; these two knots are not pass-equivalent and additionally, the right- and left-handed trefoils are pass-equivalent. Now we can define the Arf invariant of a knot to be 0 if it is pass-equivalent to the unknot, or 1 if it is pass-equivalent to the trefoil. This definition is equivalent to the one above. Vaughan Jones showed that the Arf invariant can be obtained by taking the partition function of a signed planar