Love Knot

"In the old days a love-sick sailor might send the object of his affections a length of fishline loosely tied in a true-lover's knot.

If the knot was send back as it came the relationship was static. If the knot returned home snugly drawn up the passion was reciprocated. But if the knot was capsized -tacit advice to ship out."

...from Annie Proulx's 'The Shipping News', p-2006, p.13