The fact is, for a lot of these applications, it’s just data. The ceremony of object wrappers doesn’t carry its weight. Just put the data in a hash map (or a list if you don’t need the bits “labeled”) and then process the collection with your iterate, map, and reduce functions

Explaination of the overview pyramid

State changes, write-only domain model, behaviours vs. setters and getters

Good reference to distinguish the harder to differentiate patterns like adapter, facade, proxy

An Introduction to Polymorphism and Design Patterns

List of object oriented code smells

pecl/runkit, pecl/intercept, AspectPHP, GAP