diff --git a/README.md b/README.md
index a4cad17..c0bc959 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,9 @@ DoublePendulum.py
 
 Duffing.py
 	Duffing oscillator.
+	
+FlipPhone.py
+	Flipping iPhone simulator. (See https://galileo-unbound.blog/2021/10/10/physics-of-the-flipping-iphone-and-the-fate-of-the-earth/.)
 
 Flow2D.py
 	Simple flows for 2D autonomous dynamical systems.  Options are: Medio, van der Pol, and Fitzhugh-Nagumo models.