explain arguments more

Akuli · Akuli · commit 2fc660a890d7 · 2016-10-21T16:22:25.000+03:00
diff --git a/defining-functions.md b/defining-functions.md
@@ -199,6 +199,10 @@ and prints it. Maybe a custom function could also take an argument?
 >>> 
 ```
 
+Here `message` is an argument. When we call the function we'll get a
+local variable called message that will point to whatever we passed
+to `print_twice`.
+
 This function can be called in two ways:
 
 - Using a **positional argument**.
@@ -213,6 +217,9 @@ This function can be called in two ways:
     >>> 
     ```
 
+    When the function was running it had a local `message` variable
+    that pointed to `"hi"`. The function printed it twice.
+
     Positional arguments are great for simple things, but if your
     function takes many positional arguments it may be hard to tell
     which argument is which.
