private void FixedUpdate()
{
    floorTiles1.transform.position -= new Vector3(GameManager.instance.worldScrollingSpeed, 0f, 0f);
    floorTiles2.transform.position -= new Vector3(GameManager.instance.worldScrollingSpeed, 0f, 0f);

    if (floorTiles2.transform.position.x < 0f)
    {
        floorTiles1.transform.position += new Vector3(36f, 0f, 0f);

        var temp = floorTiles1;
        floorTiles1 = floorTiles2;
        floorTiles2 = temp;
    }
}