Quatro Cantos

Purpose

Four junctions, four tracks each, one command per junction. Operating a junction shifts its tracks and then passes the change on: fixed connections copy colors into the two neighboring junctions, so no maneuver is ever local. The mechanism is the object on display; finding a satisfactory configuration is the task put to the user.

Origin

The mechanism began with a single question: what if the Rubik’s cube were a square, in two dimensions? As in the cube, no maneuver is local: turning one junction alters its neighbors.

Operation

The whole mechanism is a pure reducer over immutable state. A ROTATE action shifts the junction’s four-track array, then walks a fixed connection map, in which each junction feeds exactly two neighbors from one track index into another, and writes the rotated values through. The interface is plain DOM: each track is an absolutely positioned segment painted in one of the four line colors, and Vue simply re-renders whatever the reducer returns.

Keeping the logic reducer-shaped means the mechanism can be verified and improved without altering a single element on screen.

Operating records

• Counter-clockwise rotation exists in the reducer but is disabled in the interface: one-way rotation proved the more interesting task. A maneuver cannot be undone, only carried around the full turn.
• There is no completion check yet. The facility is, in fact, experimental: the loop that would make it a complete task (a goal state, a signal of completion, a reset with meaning) is the known next stage.
• In the Terminal’s renovation the glowing wires gave way to metro lines. The board’s colored edges now read as terminals, which suggests a goal state the mechanism does not yet check.