Exactly. I guess that it is not possibly add more child nodes at one node later, because in canvas-brush pattern when you pass a message like #with: to the actual node (a brush) its contents is written inmediately in the underlying stream of characters (within canvas), thus if at continuation you add another siblings nodes of first one, its contents will be also written in the stream immediately,�and you no longer have a chance to add more children to the first node.