One brain teaser that's currently stumping people is finding the right silhouette. The image below features a mother and a daughter hugging each other and the challenge that arises for you is to ...

Expanding the eye band causes the eyeball to shorten. In short-sighted people this will bring the retina forward to intersect with the focused light, making far-off images sharp and clear again.

Silicon Valley has a new shiny toy. It's a silver orb outfitted with eyeball-scanning cameras intended to distinguish humans from machines in the era of ever-developing artificial intelligence.