import flash.display.BitmapData;
import flash.geom.*;
function takeSnapshot(mc:MovieClip):BitmapData {
var sp:BitmapData = new BitmapData(mc._width, mc._height, true, 0×000000);
sp.draw(mc, new Matrix(), new ColorTransform(), “normal”);
return sp;
}

box2_mc.attachBitmap(takeSnapshot(box1_mc), 1);