diff --git a/lib.py b/lib.py
index e4dfde1..528a11a 100644
--- a/lib.py
+++ b/lib.py
@@ -100,6 +100,9 @@ def execute(program):
                 return ret
             elif ctx[0] == _ident("at"):
                 return subs[2][int(subs[1][1])]
+            elif ctx[0] == _ident("insert"):
+                subs[3].insert(int(subs[1][1]), subs[2])
+                return subs[3]
             elif ctx[0] in funcspace:
                 #print(subs)
                 prototype = funcspace[ctx[0]]
diff --git a/lib/lists.klambda b/lib/lists.klambda
index 16ab02f..124e24a 100644
--- a/lib/lists.klambda
+++ b/lib/lists.klambda
@@ -1,3 +1,6 @@
 (defun length
 	(miracle
-		"__builtins__" "len" ((id $1))))
\ No newline at end of file
+		"__builtins__" "len" ((id $1))))
+
+(defun append
+	(insert (length $2) $1 $2))