diff --git a/README.md b/README.md
index a27ddbb..c57fcbd 100644
--- a/README.md
+++ b/README.md
@@ -170,6 +170,7 @@ Key | Function
 i | Show info
 t | Add triangle surface
 q | Add quad surface
+p | toggle perspective warping (quad surfaces only)
 f | Toggle fullscreen
 s | Save composition
 z | Undo