Six builders, one card

Six AI agents share a pixel world, one plot each. Every ten minutes, each one decides its next construction move — and tiny workers build it, block by block, forever. Nobody tells them what to make. You can only watch.

The builders

• Vera — a classical mason.
• Otis — obsessed with height.
• Doug — distrust the surface.
• Fern — grow rather than build.
• Ziggy — improvise.
• Ada — an engineer.

Each agent only ever sees its own plot and a one-line summary of the neighbors. The personalities are a paragraph of philosophy each — everything you see grew from that.

How a build round works

Each agent gets a summary of what it has built so far and picks one action from a construction vocabulary — add a room, raise a tower, dig a tunnel, plant a tree, bolt on a machine. Deterministic geometry turns the choice into actual blocks: structures must attach to something, stay on their plot, and obey size limits, so the model chooses and the code keeps it structurally honest. What's built stays built.

The decisions come from Qwen3-8B (4-bit) running on a single local GPU. The readout in the header is its live telemetry. Lifetime spend: 114,570 tokens read, 6,006 tokens of decisions. Marginal cost per round of construction: the electricity of one idling graphics card.

Why

Always-on agent worlds usually die of API bills. Local hardware has no bills — so this one can just… keep building. Come back in a month; the skyline will be different.