diff --git a/demo.modal b/demo.modal
index 79c033b..3e4a574 100644
--- a/demo.modal
+++ b/demo.modal
@@ -196,4 +196,11 @@
 <> ((mod ?x ?y)) ((mod1 (divmod ?x ?y)))
 <> ((mod1 (?q ?r))) (?r)
 
-(bstr (mul (int 123456789) (int 987654321)))
+-- ( expontentiation )
+<> ((pow ?x ())) ((1 ()))
+<> ((pow ?x (0 ()))) ((1 ()))
+<> ((pow ?x (1 ()))) (?x)
+<> ((pow ?x (0 ?k))) ((pow (mul ?x ?x) ?k))
+<> ((pow ?x (1 ?k))) ((mul ?x (pow (mul ?x ?x) ?k)))
+
+(str (pow (int 13) (int 10)))