Помогите разобраться в примере

[Andromed]

class testclass {
	private var Arr:Array = [];
	private var ExtCanvas:MovieClip;
	public function testclass(place:MovieClip) {
		this.ExtCanvas = place;
		this.ExtCanvas.createEmptyMovieClip("Canvas", this.ExtCanvas.getNextHighestDepth());
	}
	public function showtext() {
		if (ExtCanvas.Canvas["TextBlock"+Arr.length] == undefined) {
			ExtCanvas.Canvas.createTextField("TextBlock"+Arr.length, ExtCanvas.Canvas.getNextHighestDepth(), 0, 0, 300, 30);
		}
		var txtBlock:TextField = ExtCanvas.Canvas["TextBlock"+Arr.length];
		txtBlock.type = "dynamic";
		txtBlock.multiline = true;
		txtBlock.text = "npeBeg, kpacaB4er !!!";
		Arr.push(txtBlock);
		//
		trace(txtBlock.text);
	}
}