diff --git a/src/experimental/note.md b/src/experimental/note.md
index fcb3aac2..520016d7 100644
--- a/src/experimental/note.md
+++ b/src/experimental/note.md
@@ -11,4 +11,7 @@ to_do:
 - turtle/lsystem2
 - turtle/lsystem3
 - turtle/footprints2
-- turtle/footprints3
\ No newline at end of file
+- turtle/footprints3
+- pixel/px_union
+- pixel/px_intersection
+- pixel/px_difference