Good Luck: Triangular
I've been thinking of the whole 3 sided versus three (knot type or 6-eared and 6 petals and whatnot. Something like 3-luck is certainly good for quick file naming and shorthand, but in descriptive text when trying to be clear and unambiguous, I'm thinking to use full-on mathematical (polygonal) terminology. Especially since, as demonstrated by the case of the good luck knots the number of ears does not necessarily properly describe a many-sided knot. So all those 4-sided good luck knots I've been talking about they're all square even when they look round. *sigh*
But in any case, because pictures make a blog infinitely more interesting, here's the triangular good luck knot. Nothing tricky here, just make a 'Y' shape with bights and crown it twice. Reverse direction for the second crown for a crisper shape.