If you watched Lost you know about the smoke monster. If you didn’t watch Lost, I am sorry, this is not going to make sense.
The cabs when printing out the receipt make this noise. At first, I thought the reason why I cringed when I needed a receipt (which is often, it is strange that I travel by cab all around. I guess it is like mileage, just different) is because the noise is so loud. One day, as a smell, image, or noise can takes you back to a place. It came to me.. it is the smoke monster! Seriously, the exact sound!! Come to Shanghai and I will let you experience it for yourself, freaky.