diff --git a/21st_century_c/Makefile b/21st_century_c/Makefile
index 3cb3a98..490a45d 100644
--- a/21st_century_c/Makefile
+++ b/21st_century_c/Makefile
@@ -22,3 +22,4 @@ clean :
 	rm -f boxes
 	rm -f show_tree
 	rm -f simple_cplx
+	rm -rf *.dSYM