There was a time when computers were easy to spot: They filled rooms, blinked lights and whirred with fans. But these days, computers are becoming harder and harder to see. In fact, you've got at least one in your pocket right now.

Computers have become far, far more embedded in our everyday lives than ever before—to the point that they're becoming practically invisible. At their simplest, they take inputs, process them, and provides outputs. It's that definition, along with escalating technological progress, that's making them ubiquitous.

So, while that means that your MacBook definitely counts as a computer, and so does your smartphone, what about your car? Or your credit card? Or, as this video explores, even the road outside your home? Maybe, just maybe, invisible computing will soon make everything smart—and mean that everything around us is a computer. [Computerphile]