Puzzle 14: Traffic Jam

Visual clue. Four stamps that feature a solitary bicycle on a plain background.

The hook. Bicycles are one of the most common and efficient human-powered vehicles in the world.

Here's the trap we set. There are six bicycles on the board, but the two with riders are postal messengers and belong to the Postal vehicles group instead.

Visual clue. Four stamps showing large buses carrying passengers in various settings.

The hook. Buses provide essential mass transit for millions of people every day.

Here's the trap we set. There are exactly four buses, so none of them is hiding in another group. The catch was among the trucks and bicycles.

Visual clue. Four stamps featuring large, heavy-duty trucks used for industry and cargo.

The hook. Trucks are the backbone of global logistics, agriculture, and manufacturing.

Here's the trap we set. With six trucks and vans in all, you had to carefully exclude the two used for delivering mail: the US mail truck and the Moldovan postal van.

Visual clue. Four stamps with a clear postal clue: a US mail truck at a post office, a postman on a bicycle handing over a letter, a van marked Posta Moldovei, and a postman cycling past the Manila Post Office.

The hook. Postal services use every vehicle imaginable—from bicycles to buses—to ensure the mail gets delivered.

Here's the trap we set. The ultimate red herring! Two trucks and two bicycles were really mail carriers, and they sabotaged your Trucks and Bicycles groups until you spotted their postal clues.