  When a biological system robustly corrects component-level errors, the direct
pressure on component performance declines. Components may become less
reliable, maintain more genetic variability, or drift neutrally in design,
creating the basis for new forms of organismal complexity. This article links
the protection-decay dynamic to other aspects of robust and complex systems.
Examples include the hourglass pattern of biological development and Doyle's
hourglass architecture for robustly complex systems in engineering. The deeply
and densely connected wiring architecture in biology's cellular controls and in
machine learning's computational neural networks provide another link. By
unifying these seemingly different aspects into a unified framework, we gain a
new perspective on robust and complex systems.
