The Waterfall Metaphor as Metaphor

The waterfall model for software development works poorly as a conceptual metaphor .

Royce 1970 did not name the waterfall metaphor, but he introduced the diagram that inspired the name:

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It’s easy to see why the process came to be called “waterfall.” It’s nice to envision water flowing over that series of ledges.

But that's a a horrible mistake. Water flows easily and naturally downhill. Software development isn't like that.

This is a better picture, more faithful to reality.

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Each step is *work*. Fish Ladder Analogy

Beyond implying software development is "as easy as falling off a log," there's also the Code is Down problem.