How many times have you seen the opening credits of The Andy Griffith Show? Dozens? Hundreds? Countless?

You've been fooled every time.

It seems like a simple enough set-up. Sheriff Andy and Opie walk to the fishin' hole with their poles. The boy picks up rocks and tosses them towards the water. What kid doesn't have the impulse to skip stones?

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But that iconic intro had two major hurdles, as we learned in The Boys: A Memoir of Hollywood and Family, the wonderful new autobiography by famous brothers Ron and Clint Howard. For starters, that body of water, known in Mayberry as "Myers Lake," was no fishin' hole. It is, in reality, a reservoir in Franklin Canyon Park, high above Beverly Hills. That reservoir provides drinking water to the city of Los Angeles.

So, folks can't go throwing things into it willy-nilly, no matter how famous they might be.

"The rules for filming were strict: I was only allowed three takes to throw the rocks," Ron Howard explained. "The prop department had three rocks ready to go, carefully cleaned so that their presence in the lake would not affect the potability of the water."

Aha! Sterile rocks! Well, three takes should be plenty of tries to get that stone into the water, right? Well, on the first take, little "Ronny" discovered a big problem.

"My skinny little arm was not powerful enough to get that rock into the water," Howard wrote. A quick solution was needed — they only had two more chances.

The production came up with a clever fix. Ron moved his arm as if he was throwing Rock No. 2, but secretly Reggie Smith, the prop master hiding behind a tree, threw the actual rock to get a "picturesque splash in just the right part of the frame." No third take was needed.

Opie never threw a rock in the take you see in the opening credits. A "stunt rock guy" did the action. 

Hey, Howard was just six years old. That's a hard throw.