diff --git a/setup.py b/setup.py
index 864b268..cf6e8c5 100644
--- a/setup.py
+++ b/setup.py
@@ -1,4 +1,4 @@
-from setuptools import setup
+from setuptools   import setup, Extension
 from Cython.Build import cythonize
 
 setup(
@@ -11,5 +11,10 @@ setup(
     packages     = [
         'hexagram'
     ],
-    #ext_modules  = cythonize("py/hexagram/*.pyx"),
+    ext_modules  = cythonize(
+        Extension(
+            "*", ["py/hexagram/*.pyx"],
+            include_dirs = ["./include", "/usr/include/cairo"]
+        ), language_level = 3,
+    )
 )