Weapons without blades like the staff and half-staff (jo) can be thought of as radially symmetric because there is no need to hold them in any orientation in order to strike an opponent. For maces with a square cross section this is the case also – whether defending against an incoming blow or delivering a strike it does not much matter whether a flat surface or an angled surface is leading.
Tactically, turning a trident parallel to an opponent’s axis of attack so the tines are in a column perpendicular to the floor seems ill-advised as it reduces horizontal protection. There’s a fair amount of debate about whether all three tines should have the same effective length: the argument goes that shorter side tines provide no advantage and that most of the time an enemy need only focus on following the longer central tine – track it and block it and the side tines are not much of a threat. I have never heard of a five-tined “fork” weapon with four tines arranged around a center tine like the five side of a six-sided die.