override public void Execute(float deltaTime)
        {
            int pFreq = pRandom.Next(1, 10) / this.nCurrLevel;

            AlienGrid     pGrid  = (AlienGrid)GameObjectMan.Find(GameObject.Name.AlienGrid);
            AlienCategory pAlien = pGrid.GetRandomAlien();

            // HACK don't crash pleease
            if (pAlien == null)
            {
                TimerMan.Add(TimeEvent.Name.BombSpawn, this, pFreq);
                return;
            }

            int          type          = pRandom.Next(0, 2);
            FallStrategy pFallStrategy = null;

            switch (type)
            {
            case (0):
                pFallStrategy = new FallZigZag();
                break;

            case (1):
                pFallStrategy = new FallDagger();
                break;

            case (2):
                pFallStrategy = new FallStraight();
                break;
            }
            type = pRandom.Next(0, 2);
            GameSprite.Name pGameSpriteName = GameSprite.Name.Uninitialized;
            switch (type)
            {
            case (0):
                pGameSpriteName = GameSprite.Name.BombZigZag;
                break;

            case (1):
                pGameSpriteName = GameSprite.Name.BombDagger;
                break;

            case (2):
                pGameSpriteName = GameSprite.Name.BombStraight;
                break;
            }

            Bomb pBomb = new Bomb(GameObject.Name.Bomb, pGameSpriteName, pFallStrategy, pAlien.x, pAlien.y);

            pBomb.ActivateCollisionSprite(this.pSB_Boxes);
            pBomb.ActivateGameSprite(this.pSB_Bombs);

            GameObject pBombRoot = GameObjectMan.Find(GameObject.Name.BombRoot);

            Debug.Assert(pBombRoot != null);

            pBombRoot.Add(pBomb);
            TimerMan.Add(TimeEvent.Name.BombSpawn, this, pFreq);
        }