Finding that stopping point is always hard. With intuitive painting, you have to "feel" the end of the piece. That line when you've gone to far is pretty hazy.
Walk in the park
http://fav.me/d28wsza
Became
Artery
http://fav.me/d292s1i
Which in the same night became...
Wetland
http://fav.me/d292xbx
Hmmm where to go from here.