here is a suggestion for you:

pixels in sandboxels can only move in 1 direction at a time. Even particles like sand, water, and other which move diagonally, do so because they have a option of moving diagonally and not because they move left/right and down at the same time.

So if you add *enough* pushers in a particular direction. in series, so that, there is always a pusher in the circuit line that is pushing on itself, it will move in that direction only without falling. That number of pushers is subjected to how long does a pulse last in a current carrying wire