+ Base Case: Rather than a **condition** to keep running, recursive algorithms reach a point to **stop and return**. This point is commonly referred to as the **base case**.
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+ Each time you call the function, an argument must change. One argument in particular should be changing *towards* the **base case**.
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+**Establish your base case**. Figure out when the recursion ends! Without a place to stop you’ll wind up overflowing the [call stack](https://en.wikipedia.org/wiki/Call_stack).