diff --git a/wasm/demo/snippets/mandelbrot.py b/wasm/demo/snippets/mandelbrot.py
index a2de7e8ae..f8549188e 100644
--- a/wasm/demo/snippets/mandelbrot.py
+++ b/wasm/demo/snippets/mandelbrot.py
@@ -3,6 +3,7 @@ from browser import request_animation_frame
 w = 50.0
 h = 50.0
 
+# to make up for the lack of `global`
 _y = {'y': 0.0}
 
 def mandel(_time_elapsed=None):