One step of a MoveRoute, run in order against a GridMover. Unlike GridMover.moveBy
itself, a route step does not always know its own dx/dy up front - random, toward
and away resolve a direction only when the runner actually reaches that step, against
wherever the mover and (for toward/away) the target happen to be at that moment.
One step of a
MoveRoute, run in order against aGridMover. UnlikeGridMover.moveByitself, a route step does not always know its owndx/dyup front -random,towardandawayresolve a direction only when the runner actually reaches that step, against wherever the mover and (fortoward/away) the target happen to be at that moment.