void FixedUpdate()
{
// Color c = this.GetComponent<Renderer> ().sharedMaterial.color;
// c.a = 0.8f + Mathf.PingPong (Time.time * FLASH_SPEED, 0.2f);
// this.GetComponent<Renderer> ().sharedMaterial.color = c;
transform.localPosition = new Vector3(
transform.localPosition.x,
transform.localPosition.y,
origZ - 0.05f + Mathf.PingPong (Time.time * FLASH_SPEED, 0.1f)
);
}