Merge pull request #26 from elliewix/patch-3

adding recipe card analogy about function defs

_episodes/14-writing-functions.md

@@ -47,6 +47,9 @@ def print_greeting():
 *   Defining a function does not run it.
     *   Like assigning a value to a variable.
 *   Must call the function to execute the code it contains.
+*   The commands for the function are read and stored after the `def` block, but not actually executed until the function is called later on.
+    *   Imagine getting a recipe card and keeping it in your kitchen.  You can cook it anytime, but you haven't completed any of the steps until you start that cooking process.
+    *   This means that Python won't complain about problems until you call the function.  More specifically, just because the definition of a function runs without error doesn't mean that there won't be errors when it executes later.
 
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 print_greeting()