Built carefully, extremely tiny, or single purpose. "Do one thing and do it well" - the unix philosophy, and why I still use cd, ls (dir on windows) today. If

Built carefully, extremely tiny, or single purpose. "Do one thing and do it well" - the unix philosophy, and why I still use cd, ls (dir on windows) today. If a project exceeds two functions its probably doomed to become either redundant or broken. If a project does one thing well, even if something else uses it, you can always decompose to it (your software is always useful, even when somebody writes the fancy bells and whistles version).