Many of us step into an elevator and immediately check our reflection or snap a quick selfie without thinking twice about why ...

I wake up in the morning and look in the mirror. I shower and do my hair and makeup in front of a vanity mirror, then get dressed with the help of my full-length mirror. I have three mirrors in my ...

Introduction Can you imagine a bouncy ball that could bounce back and forth between two walls, infinitely—that is, forever? Wouldn't that be amazing? What if, instead of a ball, light was bouncing ...