clauses
% No valid edges.
place("Background",1,0.0,0.0).
place("Background",2,1.0,0.0).
place("Background",3,1.0,1.0).
place("Background",4,0.0,1.0).
place("Background",5,0.5,0.5).
place("Foreground",1,0.05,0.05).
place("Foreground",2,0.9,0.1).
place("Foreground",3,0.9,0.9).
place("Foreground",4,0.1,0.9).
place("Foreground",5,0.5,0.5).
edge("X","Edges",1,1,2).
edge("Y","Edges",2,2,3).