Reversing movement directions

So basically I’m trying to make two cubes move in opposite directions across a lane (obstacles for the player). I’ve managed to get the cubes to go right to left, but I need one to be going left to right to make them move in opposite directions.

This is what I’ve got so far:

As you can see they both start in the centre of the lane and move right to left, I want the top one to be going left first, but I’m not sure how to achieve this. I created a seperate script and put everything in from the other script but I can’t figure out what to change to make it go in reverse.

Here’s the code on the cubes:

public class EnemyCubeMotion : MonoBehaviour {

	float originalX;
	public float floatStrength = 1; // Change x pos range in Editor 
	void Start()
		this.originalX = this.transform.position.x; //Saving the original position
	void Update()
		transform.position = new Vector3(originalX + ((float)Math.Sin(Time.time) * floatStrength),
		                                 transform.position.y, //Sin  between -1 and 1

If anyone could help me out or give me any suggestions I’d really appreciate it, I’m quite new to Unity so I’m making a lot of stupid mistakes at the moment. Thanks.

Try making floatStrength = -1 for the second cube