Oh cool, thanks for responding, I have never noticed mention of a phase like this in the few things I've read about the development of drawing in children.
Not exactly related, but an interesting read on scribbling/mark making in children, I have only gotten through part of this...

http://drawingwriting.com/scribReQ.html

We go through ups and downs around here, sometimes related to whether we have a stack of fresh paper readily available! They do go through the paper. wink

https://twitter.com/asimom, https://contributingfactor.wordpress.com