And Here a Miracle Occurs

There's an old math joke that involves a complicated formula that goes on for a while and then the mathematician writes "and here a miracle occurs" and then goes on with the equation. Another mathematician standing nearby says, "Perhaps you could be more specific in this step here." My partner, who was a math minor in college, had a t-shirt with this on it because she had a professor who tended to skip several steps in the equation saying that those were "patently obvious to the casual observ...