class AirBalloon : Balloon {

    override fun begin() {
        super.begin()
        direction = SOUTH
    }

    override fun roll( dx : int ) {
        super.roll(dx)
        actor.direction -= Angle.degrees(90 * dx)
    }

    override fun myTurn() {
        val south = lookSouth()
        if (south.squashable( SOUTH )) {
            moveSouth()
        } else {
            if ( south.rounded( NORTH_WEST ) && canRoll(-1) ) {
                roll( -1 )
            } else if ( south.rounded( NORTH_EAST ) && canRoll(1) ) {
                roll( 1 )
            }
        }
    }

}