using System;

public class Program

{

    public static void Main()

    {

        public class movingPlatform : MonoBehaviour

{

    public float counter = 0f;

    float multiplier = 1f;

    public Vector3 originalPosition;  // this defines the position you put the object in the scene as its original position

​

    void Start()

    {

        originalPosition = transform.position;

    }

​

    void Update()

    {

        counter = counter + Time.deltaTime * multiplier * 5; // the digit after multiplier is the speed, because it is the seconds * that number

        transform.position = originalPosition + new Vector3(counter, 0, 0);

​

        if (counter > 5f)

        {

            counter = 5f;

            multiplier = -1f;

        }

        if (counter < -5f)

        {

            counter = -5f;

            multiplier = 1f;

        }

    }

}

    }

}