The third-system effect describes a simple system rising like a phoenix out of the ashes of a system that collapsed under its own complexity.
A notorious ‘second-system effect’ often afflicts the successors of small experimental prototypes. The urge to add everything that was left out the first time around all too frequently leads to huge and overcomplicated design. Less well known, because less common, is the ‘third-system effect': sometimes, after the second system has collapsed of its own weight, there is a chance to go back to simplicity and get it right.
Raymond says that Unix was such a third system. What are other examples of the third-system effect?