diff --git a/package.lisp b/package.lisp
index ecd77b8..2fdd1d6 100644
--- a/package.lisp
+++ b/package.lisp
@@ -7,4 +7,4 @@
   (:use :common-lisp :sdl2)
   (:export :line :circle :rectangle :centre-rectangle
 		   :define-transform :translate :scale :rotate
-		   :overlay :graphics-context :cleanup :display-frame))
+		   :overlay :simulation :define-simulation))