Open Fly

Ever thought horror games just aren't horrifying enough? Then behold a real-life horror: a fruit fly, made to play Open Doctrines against its will, so that it can draft you into a war. (Totally worth the psychological-horror tag, by the way.)

Now the part that is true. This is a simulated fruit-fly brain playing a grand strategy game, live, in your browser. It has 138,639 neurons, wired the way the FlyWire connectome maps a real adult Drosophila brain. They fire turn after turn while their country goes to war, runs out of money and sometimes disappears from the map.

Nothing here is pre-recorded, and nothing was trained. The brain runs on your machine, and every order you see comes from its spikes.

What you are watching

• A fly at a desk, playing Open Doctrines on the monitor. Move the camera anywhere in the room.
• Beside it, the brain itself. Every point is a neuron, and it lights up when that neuron spikes.
• On the wall, the whole world, redrawn every turn.
• On the monitor, the fly's country up close and the orders it just gave.

How a fly plays a strategy game

It does not know it is playing one. Each turn, what happened to its country becomes stimulation of real sensory neurons:

• Sugar (20 neurons): land gained, and a budget in surplus.
• Bitter (20): land lost, a budget in deficit, and new wars.
• Water (18): money in the treasury.
• The antenna's Johnston's organ (145): how many wars it is fighting.

Then the whole brain runs for 200 milliseconds of simulated time. Its 1,299 descending neurons carry commands from a real fly's brain to its body. Here they are dealt into 39 groups, one for each action the game offers, and the groups that fire most decide what the country does: fund industry, build a fort, repress, conciliate, bombard.

That mapping is ours, not the fly's. It was written down before the fly played a single turn. The brain is the published model from Shiu et al. (Nature, 2024), ported to JavaScript and checked spike for spike against the original.

What it is not

No flies were harmed: nothing here is alive. It is not a living fly, it did not learn to play, and it is not good at it. In our tests it ended up holding less land than a country that did nothing at all. A fruit-fly brain evolved to find food and avoid being eaten, not to run Sweden in 1914. That is the point.

Pick the world

• Choose any map that ships with Open Doctrines, or import your own .odmap from the game's map editor.
• Choose any country, or let it pick one at random.
• If the fly's country is wiped out, the same game starts again with a new seed.

It follows the game

Every time Open Doctrines releases, Open Fly rebuilds against the new version, lets the fly play it, and posts the result here as a devlog.

Play it yourself

Open Doctrines is a free, source-available grand strategy game that runs in your browser. It has six historical scenarios, a map editor and multiplayer. You will almost certainly do better than the fly.

Credits

• Brain model: Shiu et al., "A Drosophila computational brain model reveals sensorimotor processing", Nature 634 (2024).
• Connectome: FlyWire, Princeton University and collaborators, public release 783, licensed under CC BY-NC 4.0 and converted for the browser. Cite Dorkenwald et al., "Neuronal wiring diagram of an adult brain", and Schlegel et al., "Whole-brain annotation and multi-connectome cell typing of Drosophila", Nature 634 (2024). The full list of citations and the changes made are in the page's data licence.
• Game, fly and page: Pr1nted.

You need a recent desktop browser. About 65 MB downloads the first time. The brain runs on your CPU in background threads, so a laptop's fan may notice.