In Sweden, everybody knows how to tie the horses. They "must" be parallel, but opposite - like this:
(well, they can be the other way around,too)
Then I found a picture on the 'net - a picture that can't be copied, only linked to.
From what I can see, the horses are tied in a pattern I have never seen before:
Let's see if this gives the right photo:
Museo-Laboratorio di tessitura a mano Giuditta Brozzetti is courtesy of TripAdvisor.
Or is she using just three shafts? I can't see the fourth, but it also does not look like the horses are tied two-to-one-shaft...
If they are, they still look like a "different" style.
This is how three shafts "should" be tied, according to Swe traditions:
Either tie one shaft to both ends of one horse, the other horse to the two other shafts (works best, IMO), or tie both horses to the middle shaft.