To call someone on a cellphone, you just tap the numbers on the screen, or maybe just their name. But even just 20 or 30 years ago, some phones still had a "rotary dial." The spinning wheel had a hole for each digit from 0 to 9. To dial a number, you stuck your finger in each digit's hole and spun the wheel, then let go so it could spin back and make that many clicks. For 9 and 0 you had to wait for 9 and 10 clicks. By the time the person answered, you'd forgotten why you had called!