diff --git a/hs-logo.cabal b/hs-logo.cabal
--- a/hs-logo.cabal
+++ b/hs-logo.cabal
@@ -1,5 +1,5 @@
 Name:                hs-logo
-Version:             0.3
+Version:             0.4
 Synopsis:            Logo turtle graphics interpreter
 Description:         Interpreter for the Logo programming language,
                      specialised for turtle graphics.
@@ -40,4 +40,5 @@
                      parsec-numbers,
                      diagrams-core >= 0.5 && < 0.6,
                      diagrams-lib >= 0.5 && < 0.6,
+                     diagrams-contrib >= 0.1 && < 0.2,
                      diagrams-svg >= 0.3 && < 0.4