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Darkwaar18

Posted Oct 1, 2026, 12:00 AM by Mathieu Ledru Mathieu Ledru

Darkwaar is an experiment in creating and publishing small playable ideas regularly.

Today's puzzle

Today's Darkwaar is Darkwaar18, Core Leak.

Software tends to accumulate structure. A running system can keep pieces that still exist, still connect, and still do nothing the output needs. Darkwaar18 is a small portrait puzzle about that:

How much can you remove before the system stops being itself?

The board is one network. Sources send a light along the wires. An output is satisfied only when that light arrives. Some nodes sit off to the side. Some look necessary and are not. A diamond waits until every light it needs is still there. Later, you choose how to spend the graph you have left.

A full session is five stages of the same idea, a few minutes once the shapes are familiar.

How to play

  • Tap a node, then PRUNE
  • RUN sends the light through what remains
  • A node that never helps the output is leak
  • UNDO puts the last node back. RESTART restores the stage
  • On the last two stages, PULSE spends the graph you have. LOCK is cheap only when the waste is already gone

The calm ending is a smaller graph that still lights.

Play on itch.io

Play Darkwaar18 in the browser: https://darkwoodcom.itch.io/darkwaar18

Screenshots

The last stage, before anything is removed

Pulse of the calm core still costs more than the budget

Lock, once only the live core remains

The core

Darkwaar18 asks one question: what is the smallest core that still behaves like the board you started with?

A long description can shrink and still mean the same thing. Prune until every output still lights. What remains is the core. A node that never helped that light is leak, even when it sits on a wire, and even when it lights on its own.

The same core can be spent in two ways. Pulse walks whatever graph is still there, so leftover structure costs you. Lock is the cheap commit, and it stays cheap only after the waste is gone. Three failed locks start the stage over. Pulse never does.

Five stages are five pictures of one network. The first boards teach a loose node, a spare path, and a join that waits for every light it needs. The last two add the choice. The calm ending is a lock of the live core, not a pulse of the noisy graph.

Development note

One graph, five authored stages, Godot primitives only. Source lives in the Darkwaar monorepo: github.com/darkwood-com/darkwaar.

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