diff --git a/lib/joy.mli b/lib/joy.mli
index b45d4da..cd9eb7d 100644
--- a/lib/joy.mli
+++ b/lib/joy.mli
@@ -12,7 +12,7 @@ val complex : shapes -> shape
 val rotate : int -> shape -> shape
 val translate : float -> float -> shape -> shape
 val scale : float -> shape -> shape
-val compose : ('a -> 'b) -> ('b -> 'c) -> 'a -> 'c
+val compose : (shape -> shape) -> (shape -> shape) -> shape -> shape
 val repeat : int -> (shape -> shape) -> shape -> shape
 val context : Context.context option ref
 val set_color : float * float * float -> unit
diff --git a/lib/transform.mli b/lib/transform.mli
index 706948a..712f823 100644
--- a/lib/transform.mli
+++ b/lib/transform.mli
@@ -1,5 +1,5 @@
 val translate : float -> float -> Shape.shape -> Shape.shape
 val scale : float -> Shape.shape -> Shape.shape
 val rotate : int -> Shape.shape -> Shape.shape
-val compose : ('a -> 'b) -> ('b -> 'c) -> 'a -> 'c
+val compose : (Shape.shape -> Shape.shape) -> (Shape.shape -> Shape.shape) -> Shape.shape -> Shape.shape
 val repeat : int -> (Shape.shape -> Shape.shape) -> Shape.shape -> Shape.shape
\ No newline at end of file