何となくです。

/**
 * Copyright Maeda_addevent ( http://wonderfl.net/user/Maeda_addevent )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/9JCe
 */

package {
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import flash.events.Event;
    import flash.ui.Mouse;
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.geom.Point;
    [SWF(width=465,height=465,backgroundColor=0xFFFFFF,frameRate=60)]
    public class FB0027 extends Sprite {
        public function FB0027() {
            stage.addEventListener(MouseEvent.MOUSE_DOWN,xDown);
        }
        public function xDown(e:MouseEvent):void {
            var mySprite:Sprite=new mySprite()  ;
            mySprite.x=mouseX;
            mySprite.y=mouseY;
            addChild(mySprite);
            mySprite.addEventListener(Event.ENTER_FRAME,xEnter);
        }
        public function xEnter(e:Event):void {
            e.target.y += 3;
            if (e.target.y >= 465) {
                e.target.removeEventListener(Event.ENTER_FRAME,xEnter);
            }
        }
    }
}

import flash.display.Sprite;
import flash.events.Event;
class mySprite extends Sprite {
    public var myNum1:Number = Math.random()*100;
    public var myNum2:Number = Math.random()*100;
    public function mySprite() {
        this.graphics.lineStyle(1,0x1F1F1F,1,false,"none");
        this.graphics.drawRect(0,0,myNum1,myNum2);
    }
}