private void spawnPowerup()
    {
        // Choose random spawnpoint location
        Transform spawnpoint;
        int       spawnIndex = new System.Random().Next(0, powerupSpawnpoints.Length - 1);

        spawnpoint = powerupSpawnpoints[spawnIndex];

        // Spawn
        PowerupPongPowerup powerup = Instantiate(powerupPrefab, spawnpoint.position, Quaternion.identity, powerupObjects);

        powerup.GetComponent <NetworkedObject>().Spawn();
        spawnedPowerups.Add(powerup);
    }
    public override void NetworkStart()
    {
        powerupPrefab   = Network.GetPrefab <PowerupPongPowerup>("PowerupPongPowerup");
        powerupObjects  = new GameObject("Powerups").transform;
        spawnedPowerups = new List <PowerupPongPowerup>();


        if (IsServer)
        {
            // Repeated spawning powerups
            InvokeRepeating("spawnPowerup", 2, 8);
            InvokeRepeating("spawnPowerup", 6, 8);
        }
    }