Shooting multiple arrows horizontally?

[Jaguarvox]

on right click:
    shoot arrow at speed 2
    push last shot projectile right at speed 0.5
    shoot arrow at speed 2
    push last shot projectile left at speed 0.5

This should makes the arrow goes not center of your crosshair but slightly left and right, but it doesn't when you are not facing north, south, west or east because the "right" and "left" only determines which direction you are facing. In result, the arrow goes straight instead of spreading if you are facing towards north east.

How can I solve this problem?

 

[MCProHost]

[%Number%[(north[(east|west)][(south[(east|west)][(east|west)[(above|over|up|down)[ward(below|under[neath]|beneath)

Sorry, I dont spoon feed.

 

[Jaguarvox]

[%number% [(north[(east|west)][(south[(east|west)][(east|west)[(above|over|up|down)[ward(below|under[neath]|beneath) [%direction%]
[%number% [[(direction|horizontal direction|facing|horizontal facing) of %entity/block% (of|from)]
[%number% [[(direction|horizontal direction|facing|horizontal facing) (of|from)]
[%number% [(in[ ]front [of]|forward[s]|behind|backwards|right|left) [of])
[%number% [(in[ ]front [of]|forward[s]|behind|backwards|right|left) [of])

Any of those does not solve my problem. If you are pushing the arrows while looking at north east exactly, it does not push the arrows sideways because the value of right/left will be always zero.