The scene
Toy Fair · Central trackThe fair’s centrepiece is a clockwork train with three carriages: copper, blue and white. A box of prizes was carried in the middle carriage and was found empty after the demonstration.
Only one lid was opened. To identify who opened it, first reconstruct the carriage movement, then find the person with the key to the corresponding lid.
What we know for certain
The box stayed in the same carriage throughout and could not pass to another. One of these three people opened that carriage and removed the prizes using their own key. Nobody lent out keys. The position changes and records are reliable.
The three accounts
Clara Nogués
Restorer«My key opens the copper carriage. Nobody asked to borrow it during the fair.»
Omar Serra
Demonstration train driver«I held the blue carriage’s key. The position where it was seen may be misleading.»
Eva Pons
Prize organiser«My key belongs to the white carriage. It does not open either of the other lids.»
Examine the evidence
0 of 5 openedOpening these five clues does not cost points.
01The initial loading
Before any movement, the box was placed exclusively in the second carriage, counting from the locomotive.
02The only manoeuvre
After loading, the first and third carriages swapped places. Then the second and third swapped. The record treats this as one two-step manoeuvre, in that order.
03The final order
At the end of the manoeuvre, the order from the locomotive was white, copper, blue. It was not changed again before the empty box was discovered.
04The locks
Clara opens copper, Omar blue and Eva white. Every lock is different, and no key fits a second lid.
05The opening record
The box’s sensor confirms that the prizes were removed after the manoeuvre. It gives neither colour nor position; the box was still inside the carriage in which it had been loaded.