diff --git a/README.md b/README.md
index c053cc6..ac3db28 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,7 @@ Lamb treats each λ expression as a binary tree. Variable binding and reduction
  - PyPi package
  - Cleanup warnings
  - History queue
+ - `W` isn't fully expanded. Why??
 
 
 ## Todo: