A key design feature shared by many 100-year-old barns and some modern skyscrapers is that the external shell carries the building's load with a minimal use of internal columns for support. Internal floors and walls, if any, function in a structural way to stiffen the building.

The eye is an amazing instrument, but it does not function alone. Even with visual receptors rapidly sending data along the optic nerve, no mental image will form at all unless the brain is properly equipped to manage the input. One data processing feature of the brain enables what is called perceptual stability.

Sea urchins are spiny marine animals. Some of them like to hide in holes that they dig out of limestone in the ocean floor, using teeth that are ground down and yet remain sharp. What makes these teeth so special that they can drill through rock and not go blunt?

In American football, the quarterback can hand off the football to a team member, who then may do a handoff to another player. Exciting plays may be put together that combine several handoffs and even a pass downfield to an awaiting player who, hopefully, carries the ball to the goal.

A major achievement for design engineers is building precise control mechanisms for active processes. Lives depend on the precision in which certain processes are maintained, such as the manufacture of drugs.