diff --git a/Direct/Graph.hs b/Direct/Graph.hs
--- a/Direct/Graph.hs
+++ b/Direct/Graph.hs
@@ -7,6 +7,7 @@
 import qualified Common.Term as Term
 
 
+-- <chunk: node_type>
 data SKI
 	= S {inp ∷ Port}
 	| K {inp ∷ Port}
@@ -16,6 +17,7 @@
 	| Eraser {inp ∷ Port}
 	| Variable {inp ∷ Port, name ∷ String}
 	| Root {out ∷ Port}
+-- </chunk: node_type>
 
 instance View [Port] SKI where
 	inspect ski = case ski of
diff --git a/graph-rewriting-ski.cabal b/graph-rewriting-ski.cabal
--- a/graph-rewriting-ski.cabal
+++ b/graph-rewriting-ski.cabal
@@ -1,5 +1,5 @@
 Name:           graph-rewriting-ski
-Version:        0.5.1
+Version:        0.5.2
 Copyright:      (c) 2010, Jan Rochel
 License:        BSD3
 License-File:   LICENSE
@@ -17,7 +17,7 @@
 	base >= 4 && < 4.3,
 	base-unicode-symbols >= 0.2 && < 0.3,
 	graph-rewriting >= 0.4.4 && < 0.5,
-	graph-rewriting-layout >= 0.4.1 && < 0.5,
+	graph-rewriting-layout >= 0.4.2 && < 0.5,
 	graph-rewriting-gl >= 0.6 && < 0.7,
 	parsec >= 2.1 && < 2.2,
 	GLUT >= 2.2 && < 2.3,