Trunk Line (Arkai)

Trunk Line is one of the daily deduction puzzles on Arkai, a small portal of free browser games with no account, ads or third-party code.

Each day brings three networks, Line 1, 2 and 3, with the same rules and difficulty, worked out from the date so every player gets the same ones. Behind a switchboard, five stations labelled A to E are connected by a random tree: exactly four lines that link all five, with no loops.

Ping any two stations and the switchboard tells you how many hops apart they are along the hidden wiring, never which stations the path passes through. A distance of one means a direct line, and the game draws it for you; asking the same pair again is free. Switch to Mark mode to add lines you have deduced without pinging, then press Check. Every new ping costs a point and a wrong check costs two, and matching the par, which is what Arkai's own solver needed for that network, earns a star. Results can be shared without spoilers, and every earlier day stays playable.

It is a compact puzzle about graphs and distances. It suits players who like pure logic with very few moving parts.