Here is a small example showing how choosing good variable names can make a huge difference. Look at the following code block, and see how long it takes you to work out what it does. If you find it takes you a while, look at the improved code below that and see how much easier it is! Even with short variables that are words, not being descriptive makes debugging very difficult. Using letters on their own is frequently worse. Both code blocks are functionally identical, only variable names are changed.
What is Whitespace? Most modern programming languages do not consider white space characters (spaces, tabs and newlines) syntax, ignoring them, as if they weren't there. We consider this to be a gross injustice to these perfectly friendly members of the character set. Should they be ignored, just because they are invisible? Whitespace is a language that seeks to redress the balance. Any non whitespace characters are ignored; only spaces, tabs and newlines are considered syntax.
This almost made it to an "A to B" post, but unfortunately it was a bit too simple.