that would be 4 way. From 3+i5 , you can get to 3(+/- 1) + i5(+/-1). but you are right.
What i was thinking probably alludes to dimensions after all. A 3way system could be "maped" to 2d or 3d space. For example in 2d space. Each element is a point, that is connected to 3 other elements. So in 2d there are several ways to do this via e.g. lines at 120 degrees from each other, like the mercedes sign. The particular case would have some symmetries too as far as "covering" the space (2d in this case) we use to "visualise" it. If each element were connected to its 3 elements but the angles were different, arbitrary, it would still work, but it wouldnt cover 2d space the same way.
The only restriction, as i expressed it, was that you get from an element to one of its 3 branches and you can get back to that original element. We could relax that too, say, an increment would be defined by going to one of the directions (corresponding to a pre-defined angle as we see it in 2d)) by moving by some measure say exp(a*t) or even just a*t where 'a' is a global constant and t is time that always counts forward. This would imply that going from element k to any of the other 3 elements, could not get you back to k. But that doesnt really make each element the same as the others, you would have to define a fixed origin and the collection of all the elements depend on the starting point. Still possible and natural in some universe, just difficult to see i guess. This last example would probably be a case where there could be really no subtraction as we see it, only addition. There is no guarantee that you can get back to the original point for arbitrary a,x and "angles" defining the connected elements, except by chance ofcourse. We are probably digressing though, what i was looking for was a counting (co-ordinate) system.
So sticking to the restriction that you can go back to the original point form each of the 3 branches and to give another example, in 3d space this time, it could be a mesh of tetrahedra (like a four-sided die).
[which is said to be the the best 3d shape to (randomly) fill an arbitrary volume of 3d space so that most of it is covered- think of packing a container with boxes and trying to find the box design that would maximise your utilisation of the space of the container, if you just threw them in randomly without having to order them (or it would be cubes and we are done with that)]
So I think that it all falls mostly in the realm of set theory utilising geometry and just about any field after that, maybe even fractals if we choose to make it 'naturaly' exciting so thats that, i guess. Thank you for taking the time to answer. I do agree that the question looked like a Bart Simpson moment on my part, probably still is..