Dear Dr. Boli: How do potholes form? —Sincerely, Mike Gable, Director, Pittsburgh Department of Public Works.

Dear Sir: When a glacier meets the sea, the end of it begins to float on the water, forming an ice shelf. Sooner or later a crack will appear in the ice, and then a chunk will break off. And that is how potholes are formed.

No, sorry—those are icebergs. Icebergs are easy to explain. Potholes are not. No one knows how potholes are formed. Disreputable scientists will attempt to lull you into complacency with tales of freezing and thawing cycles, but those scientists have all been suborned by Big Asphalt and will tell you anything to keep you from the truth. Evidence from traffic-light cameras and convenience-store surveillance tapes shows a suspicious pattern of activity, with executives of major asphalt companies being sighted repeatedly in locations where potholes are found the next day. Is it coincidence? Dr. Boli will make no pronouncement; he merely presents the facts, and you must make the judgment yourself.