You can change the background of the top right corner of your Office apps to Circles & Shapes, Underwater, Stars, Calligraphy, Circuit, Clouds, Doodle Diamonds, etc.

At first glance, the illusion appears to show coffers, the sunken panels that decorate ceilings. On closer inspection the image has 16 hidden circles - can you spot where they are?

Our view of the early Universe may be full of mysterious circles — and even triangles — but that doesn't mean we're seeing evidence of events that took place before the Big Bang.

But dark-circle products can range from tens to hundreds of dollars. And spending more doesn’t yield better results. There’s typically no difference between drugstore and high-end products ...