Erasing and adding to objects

I think Xara should lets us to have a "virtual" eraser to our drawing, letting us to remove portions of selected object on an individual layer or across multiple layers.

The flipside of erasing is "adding to" (i.e., augmenting), a technique to add or "grow" a vector objects' boundaries—great for reshaping an existing object or to grow a vector shape from scratch. This may be especially useful when creating an unusual filled shape.

See the demo please

http://megaswf.com/view/f57b421c6b38...bdd7db583.html