"Simple Made Easy" - Rich Hickey (2011)

Caption notes

Rich Hickey separates two questions about software. Ease depends on how available and familiar a tool is and what its users can handle. To judge the simplicity of the resulting software, he looks for decisions that could be independent but have been tied together. Hiding mutable state inside a method, for instance, can still leave callers with results that vary over time. He argues for separating what the software must do from how it does it and judging designs by how well people can understand, diagnose, and change them over time.