Many extreme roller coaster these days have vertical loops. Have you noticed that these loops are never circular? Why is this?
Most of us carry credit cards and ATM cards. These, typically, have sixteen digits on the front. These digits are the unique account number for the card. For obvious reasons, just any sixteen digits will not work, they follow pattern.
We're currently experiencing colder-than-seasonal weather here in Seattle. This is causing a lot of problems with burst water pipes. Here is a picture of a couple of issues suffered by a friend of mine Ian.