Invertible Yogurt

The yogurt that I had on Saturday successfully passed the Invertibility Test* (that is, it was invertible), so I knew that it was safe to eat.

* The Invertibility Test (tm) is especially important for milkshakes, as passing this test is the only way to ensure that they are safe to consume. (For other food items, the only way to pass this test is to not be invertible.)

For more about invertible milkshakes, see Legends of Caltech III and also one of its web-only stories.

(Tip of the cap to Frances Schaeffer for taking the picture.)