FILE 02 // FORMAL LOGIC & ELIMINATION

The Evidence Must Agree

When two reliable clocks in the same station house disagree by seven minutes, an amateur looks for a liar; a logician looks at the power circuit. Fair-play deduction is built on a simple covenant between writer and reader: every suspect’s movement leaves a physical trace in time and space, and once impossible combinations are crossed out, the remaining truth must agree with every single datum on the page.

Below are three full-length deduction dossiers from our cabinet. Each includes a structured reference table, numbered evidentiary rows, a spoiler-free nudge, and a complete elimination proof.

High mountain railway platform at night with snowdrifts illuminated by carriage windows

Dossier #21 // Railway Matrix

The Bergensbanen Night Car

During the winter crossing over the Hardangervidda plateau between Geilo (21:10), Finse (22:00), and Myrdal (22:50), a sealed botanical portfolio was swapped for a decoy inside the luggage rack of Sleeper Car 3. Four passengers—Dr. Lind, Ms. Vestergaard, Herr Sohlberg, and Fru Nyström—occupied Compartments A, B, C, and D (not necessarily in that order).

Passenger	Ticket Punch Station	Dining Car Receipt	Observed Coat Detail
Dr. Lind	Geilo (21:14)	21:40 – Cardamom coffee	Dry wool lapels at 22:15
Ms. Vestergaard	Finse (22:03)	None logged	Snow-crusted cuffs at 22:10
Herr Sohlberg	Geilo (21:16)	21:55 – Mineral water	Dry wool lapels at 22:15
Fru Nyström	Geilo (21:12)	21:55 – Herbal tea	Dry wool lapels at 22:15

CLUE 01 The portfolio swap occurred at exactly 21:58 while the train stood at the Finse platform, inside the corridor directly outside Compartment C.

CLUE 02 The dining car is separated from Sleeper Car 3 by two locked vestibule doors that the conductor locks from 21:50 to 22:05 during the Finse stop.

CLUE 03 Passengers boarding at Finse enter via the rear platform of Sleeper Car 4 and cannot pass into Sleeper Car 3 until tickets are punched at 22:03.

CLUE 04 The occupant of Compartment C was inside Sleeper Car 3 at 21:58 with dry lapels and had already returned from the dining car before the 21:50 vestibule lock.

Inspect Directional Hint

Eliminate anyone trapped in the dining car at 21:55 during the Finse lock-down, and check when Finse boarding passengers gained access to Sleeper Car 3.

Verify Sealed Solution

Solution: Dr. Lind occupied Compartment C and executed the swap. Herr Sohlberg and Fru Nyström were both in the dining car at 21:55 and locked out of Sleeper Car 3 from 21:50 to 22:05. Ms. Vestergaard boarded at Finse into Car 4 and was not admitted to Car 3 until her 22:03 ticket punch. Only Dr. Lind had boarded at Geilo, finished coffee at 21:40, and returned to Sleeper Car 3 before the 21:50 lock.

Mechanical brass tide drum recording ink lines on a paper cylinder inside a harbour shed

Dossier #14 // Tide Proof

Kalmar Boathouse Elimination Notes

Supplementing our home page featured case, here is the formal three-suspect elimination matrix for the 21:00 fog-bell incident.

SUSPECT 1 Uppsala Archivist: Witnessed on the west jetty checking the tide pole at 20:55; oilskin sleeves wet with salt spray.

SUSPECT 2 Turku Botanist: Returned from the granite ridge before 20:10; remained in the kitchen tending the cast-iron stove with the archivist until 20:50.

SUSPECT 3 Bergen Hydrographer: Claimed to be reading alone in the chart room from 19:30 to 21:00 with the east vent shut—contradicted by the 45 ml paraffin burn rate.

VERIFIED BY: PARAFFIN RATE Return to Case #14

DOSSIER #07 // ACOUSTIC & OPTICAL RECONSTRUCTION

The Marstrand Quay Sightline Proof

At 22:14 on an October evening, a green-painted ketch slipped its mooring without running lights. The customs officer at the North Steps swore under oath that the hull was pitch black; five minutes later at the South Slipway, the ferry pilot logged a deep Prussian green hull with a brass name-scroll. Why did both witnesses tell the truth?

OPTICAL FACT 01 Low-pressure sodium vapour lamps (installed along the North Customs Steps) emit monochromatic yellow-orange light at 589 nanometres. Under 589 nm illumination, dark green and dark blue pigments reflect almost zero light and appear indistinguishable from matte black.

OPTICAL FACT 02 The South Ferry Slipway uses broad-spectrum halogen floodlights, restoring full colour rendering to the Prussian green hull five minutes later along the 3-knot tidal current.