How To Write Unmaintainable Code

The cardinal rule of writing unmaintainable code is to specify each fact in as many places as possible and in as many ways as possible.

... from the tongue-in-cheek article by Roedy Green

who goes on to say...

People paid no attention when I harped about how to write __maintainable code. I found people were more receptive hearing all the goofy things people often do to muck it up. Checking for unmaintainable design patterns is a rapid way to defend against malicious or inadvertent sloppiness.