"instance names"

programming flash
1

Finally I started to learn some basic as3 coding and trying to understand the frequently used stuff.
So Im trying the “attachMovie” in as,…best of all, it works :smiley:
But I have this little question about the names that flash gives the attached movies.

I made this little script:

for(var i:Number=0; i<5; i++){
    
     var mc = new MovieClip();
     mc = addChild(new Ding()); //a mc with classname Ding in the library
     mc.x = i*20
     mc.y = i*50;
     mc.addEventListener(MouseEvent.CLICK, actie);
    
}

function actie(event:MouseEvent):void{
    trace(event.target.name)
}

Traces:
instance2
instance5
instance8
instance11
instance14

Can anyone explain the logic why the numbers add up by 3 ?
And can I use these target names for anything usefull ? (I prolly still think to much as2)