Good neighborhoods provide families a lot of protection, but even the best of communities remain vulnerable to the threat of criminals invading their homes. Our human bodies are also vulnerable to foreign invaders such as bacteria, viruses, fungi, and parasites.

Charles Darwin admitted that the sudden appearance of fully formed creatures in fossil deposits was one of the biggest problems with his hypothesis that nature generated living creatures through natural selection.

A boom in affordable housing in the 1950s was helped by the invention of a distinctive multifunctional piece of equipment: the backhoe. Its strong yet relatively slender articulated arm allowed precise yet rapid placement for digging or lifting. The manipulative device is trim and fast, since hoses transfer power to it from a powerful hydraulic pump within the main chassis.

Cambrian rock layers contain fossils that represent almost every modern phylum of animal, plus many that are now extinct. One animal fossil in particular would win the weird prize, if there were one. Paleontologists have been piecing together this strange creature’s body parts, which look as though they were taken from an array of totally different sea animals.

After 100 years, automobiles still need engine oil, transmission fluid, brake fluid, antifreeze, power-steering fluid, and so on. Wouldn't it be great if just a single multipurpose fluid could be circulated from a central reservoir? Each part would use only the needed properties of the fluid, exclude detrimental properties, and then send it back.