One reason for a muddled architecture is that software often reflects the inherent complexity of the application domain. This is what Brooks called "essential complexity" [Brooks 1995]. In other words, the software is ugly because the problem is ugly, or at least not well understood. Frequently, the organization of the system reflects the sprawl and history of the organization that built it (as per CONWAY’S LAW [Coplien 1995]) and the compromises that were made along the way.

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