function ball_invisible (src, pause, speed, count){
        this.setProperties(src, pause, speed, count);
    };

    ball_invisible.prototype = new BaseSequence();
    ball_invisible.prototype.constructor = new BaseSequence;
    ball_invisible.superclass = BaseSequence.prototype;

    ball_invisible.prototype.setProperties = function(src, pause, speed, count){

		sleep.superclass.setProperties.call(this, src, pause, speed, count);

        this.sleep_counter = 0;

		this.def_prog = "invisible()";
		this.alt_prog = this.def_prog;
		this.prog     = this.def_prog;

		return this;
    };