Some people often get mixed up on which is which and end up going up and down when they want to go right and left!
A good way to remember it is that X has two lines on one side and two on the other so that means it goes right and left.
Y has two lines up and one line down but none exactly sideways like the X so that means Y goes up and down!
That's the method I use!
So hope this helped you guys!