These are slides from a lecture on Red Flags in Programming that took place at an Israeli Open Source Developers meeting.
Red flags in programming are signs that you likely made a mistake with your application design or code.
Noticing and avoiding these mistakes help us write better code, at any language.
The subject related to mostly dynamic (higher level) languages, even though the sample code is in Perl.
Clipping is a handy way to collect important slides you want to go back to later.