The Window-Ledge Reckoner

Test the roof-top deduction: could a body ride the Underground from Caulfield Gardens to Aldgate?

Holmes's masterstroke: no ticket, no blood, and a body found exactly where the line's points jolt the carriages — because West lay on the ROOF, laid there from a window ledge above the track. Try the arithmetic of the ride.

Drawn from The Adventure of the Bruce-Partington Plans (His Last Bow, 1908) — read the summary & analysis, or try The Submarine Papers, this story's game. More at the Game Room and the tool bench.