Oil on linen · 36 × 36 mm · painted by a simulated fruit fly
Full-brain recording
Walking to the palette
0%match with the picture
You steer. Its brain turns.
Move your mouse over the board: it walks toward it. Or use WASD.
Tap a paint pot below: it flies over and dips its feet. Mixed colours get mixed for you.
Hold the mouse button or Space to paint as it walks. F flies to your pointer.
Drag on the board: it walks toward your finger.
Tap a paint pot: it flies over and dips its feet.
Turn Paint on and lead it around. Fly then tap to jump.
You only choose where it goes. Its simulated steering neurons decide how to turn: watch them in the brain panel.
Leonardo da Vinci
The fly
Finished
356 of 360 strokes landed. 24 palette visits.
Painter Fly
A fly’s brain, painting your picture.
Every turn this fruit fly makes comes from a simulation of its real brain wiring: 138,639 neurons, mapped from one fly. Watch it paint a masterpiece, or take over and steer it yourself.
Loading the brain…
This fly is simulated. Every turn it makes comes from its brain.
138,639
neurons, wired as mapped in a real fly
45,669
neurons in its visual system, run live as it looks
721
facets in each eye, seeing the canvas
36 mm
canvas, smaller than a postage stamp
Pick a picture. It paints it.
The brain plans nothing: it is steered stroke by stroke toward each spot. You watch every neuron fire.
The archive
Paintings visitors made with the fly. Every one is reviewed before it appears.
How Painter Fly works
A simulated adult fruit fly paints a picture. Its turning decisions come from a computer model of its brain, built from the FlyWire wiring diagram: 138,639 neurons and about 15 million connections, mapped from electron-microscope images of one real fly's brain.
The steering loop
Every 10 milliseconds of simulated time:
Where is the next stroke?The target's direction relative to the fly's heading.
Steering neurons fire (PFL3, central complex)A target on the left drives the right-side PFL3 neurons, and the reverse.
Activity spreads through the real wiringSpikes travel neuron to neuron along the mapped connections, with the published model's timing.
Turn command neurons (DNa02, left and right)Whichever side fires harder sets the turn.
The legs turn the bodyFeet that touch the canvas near the target leave paint.
Full-brain recordings and the live brain
The Mona Lisa and The Starry Night play back runs where all 138,639 neurons were simulated alongside a physics-simulated body. Those runs reached 357 of 360 and 356 of 357 strokes.
Every other picture, including ones you upload, runs live in your browser. The live brain is the 2,117 neurons that actually fire during this task, with their 77,500 real connections and the 10,582 photoreceptors that feed them. In side-by-side tests it gave the same turn-command firing rates as the whole brain. Your picture stays on your device.
Its eyes
Each eye has 721 facets. The colour each facet sees drives the photoreceptors behind it: R1–6 respond to light and motion, R7 and R8 to colour. You can watch them glow in the brain view in the colours the fly is looking at.
Its visual system
Behind the eyes runs a second model: the fly's motion-vision system, 45,669 neurons of 65 cell types across all 721 eye columns, with 1.5 million connections laid out from the mapped wiring. It is the trained network published by Lappalainen and colleagues (Nature, 2024). Its wiring comes from the connectome; the strength of each connection type was tuned by training it to detect motion, so it is part mapped, part learned.
Each frame of what the fly sees goes through it in your browser. Its neurons light up in the brain view at the positions of the matching FlyWire cell types, and switching the eye view to Motion shows what its T4 and T5 motion detectors pick up: the colour is the direction, the brightness is the strength. Like the colour signal, this vision doesn't decide where the fly walks.
Cut neurons
The test that shows the brain is doing the steering: with the steering neurons cut, the fly reached 0 of 4 targets; intact it reached 12 of 12. In live mode you can cut them yourself and watch it lose its way.
Steer it yourself
In Steer mode you take the place of the stroke plan. Where you point becomes the input to the same steering neurons, and the brain's turn-command neurons still decide every turn, so it can overshoot, circle and correct like it does on its own. Loading paint and mixing are done for you when you tap a pot, as flights to the palette.
What's real and what isn't
Real
The wiring: every neuron and connection is from the FlyWire map.
The spikes in the brain view, and every turn decision.
What its eyes see driving its real photoreceptor neurons.
Its visual system's wiring, with connection strengths from a trained model.
The leg movements, recorded from a physics model of the fly's body.
Not real
The stroke plan and the mixing recipes are worked out from the picture by an algorithm (or, in Steer mode, by you).
The leg rhythm comes from a walking controller; the brain sets the turns.
Flights between palette and canvas are animated.
The paint is drawn, not simulated. Real flies can't paint.
Scale
The canvas is 36 mm wide, smaller than a postage stamp. The fly is about 2.5 mm long. The brush and paint tube next to it are full size.
Credits
Wiring: FlyWire Consortium (Dorkenwald et al. 2024; Schlegel et al. 2024, Nature), CC BY-NC 4.0. Brain model parameters: Shiu et al. 2024, Nature. Visual system: Lappalainen et al. 2024, Nature (trained model flow/0000/000). Fly body and walking: NeuroMechFly (Wang-Chen et al. 2024). Paintings are in the public domain. Original score, played on VSCO 2 Community Edition orchestral samples (Versilian Studios, CC0). Non-commercial project.
Cutting a neuron removes its output from the simulated brain, the same way as the lesion test. Tick one and watch what the fly does next.
This painting is a full-brain recording, so it can't change.
Add it to the archive
Your fly's painting goes into a public gallery once it has been reviewed. Only the painting and its brushstrokes are kept, plus the picture you started from if you choose to show it.
To stop abuse, the site keeps a scrambled code for your connection and browser with the submission for 30 days. No account, email or location is collected.
The originalPainted by the fly
Untitled
Make the video
Films the painting from start to finish: a real-time opening, a time-lapse with camera cuts, the reveal, and an end card that sends people to @maxlin.art.