Bombchu Mechanic

I'm trying to make this happen: https://www.youtube.com/watch?v=fzF5CEqm_rI

I've asked a friend and he's tried a few different things, but none of them work like what's in the video.

This is what I currently have: https://gyazo.com/d32fc956664f3ab39e36bfcf1b296e67 https://gyazo.com/e8320b45255f10a9930ca8ef35b48c3c

 private Rigidbody r;
 public float speed = 5f;
 public float angle = 0f;
 public Vector3 axis = Vector3.up;
 public Transform t;
 public GameObject back, top, left, right, bot;

 void Start () {
     r = GetComponent<Rigidbody> ();
     t = transform;
 }

 void Update () {
 }
 void OnCollisionEnter (Collision col) {
     if (col.gameObject.tag.Equals ("Backwall")) {
         float oldAngle = 0.0f;
         Vector3 oldAxis = new Vector3();
         transform.rotation.ToAngleAxis(out oldAngle, out oldAxis);
         transform.rotation = Quaternion.AngleAxis(oldAngle, col.contacts[0].normal) * Quaternion.AngleAxis(90, Vector3.Cross(Vector3.up, col.contacts[0].normal));
     }
 }
 void OnCollisionStay (Collision col) {
     if (col.gameObject.tag.Equals ("Botwall")) {
         var v = transform.forward * speed;
         v.y = r.velocity.y;
         r.velocity = v;
     }
     if (col.gameObject.tag.Equals ("Backwall")) {
         var v = transform.forward * speed;
         v.y = r.velocity.y;
         r.velocity = v;
     }
 }

Anyone know what I should try doing here?