Welcome to Cell Tank

Cell Tank is a playful living canvas: a petri dish full of soft-body cells you can grab, stretch, feed and fling. Everyone in the dish has an opinion about how hungry they are, and a few of them have opinions about each other. It is a toy inspired by biology—not a scientific simulation.

Feeding the dish

Cells burn energy the whole time they are alive. Pick a food from the Feed panel, then click the agar to drop a morsel — or hold the button down and sweep to pour a stream. Anything hungry nearby will smell it and swim over.

• A full cell goes blissful: closed eyes, rosy cheeks, little hearts.
• A cell that runs out of energy curls up dormant and greys out. It is not gone — drop food on it and it wakes right up.
• Keep a cell fed on protein and it swells, pinches at the flanks, then divides into two.
• Feed everyone tops up every belly at once, for when you have been neglectful.

Presets

Each preset clears the dish and plates a whole little ecosystem, ready to run. Use them as starting points and then add, feed and drag from there.

Conditions

The Conditions panel is not about the cells — it is about the puddle they live in. Four dials, all neutral in the middle, all remembered between visits. Back to normal puts every one of them back to the centre.

Tilting the dish

Hold the arrow keys and the whole plate leans — cells, food and medium all slide to the low side, and the gel pools visibly against the glass. Let go and it eases back level. On a phone, tap Phone tilt in the Conditions panel and lean the handset instead.

Things cells do to each other

• Mitochondria attach to the nearest larger cell and run a faint tether to it. Every few seconds they pulse energy down the line — enough to wake a dormant cell and push a full one past its normal limit. They spend their own reserves doing it.
• Platelets and white cells open a golden channel to an infected body cell while they scrub the infection out.
• Two of a kind that bump into each other say hello — one gets a heart, the other a music note.
• A hard knock against the glass startles a cell: it blinks and throws up an exclamation mark.
• Amoebas engulf small invaders whole and digest them.

Add a specimen

• Click a specimen in the Specimens panel. That switches you to the Place tool automatically.
• Click anywhere on the agar to drop one in.
• Switch back to Grab when you want to push things around instead of adding more.
• The Remove tool deletes whatever you click.
• The Stirring rod spins up a vortex wherever you hold it. Every species has a different membrane stiffness, so they all deform through the same current at different rates — an amoeba strings out where a diatom barely notices.

Picking things up

Every resident answers the Grab tool differently, and finding out how is most of the fun. A few of them:

• A bacterium wriggles free after a second or so. It is the only cell in the dish you cannot keep hold of.
• A diatom is glass. You get a wobble; it does not move.
• A white blood cell keeps hunting while you hold it, so you can point it at something.
• Drag a slime mould and it lays trail behind it — you are drawing roads by hand.
• A virus goes limp and plays dead, then lunges the moment you let go.
• Squeeze a yeast and it buds in your grip.
• Fling anything hard enough and it lands dizzy. Shake the whole dish — several hard changes of direction — and everybody notices at once.

Meet the cells

• Red blood cells gently drift through the dish.
• White blood cells actively hunt viruses and bacteria, popping them on contact.
• Body cells can be infected by viruses. The purple ring shows infection progress.
• Platelets seek infected cells and can heal them before the infection takes over.
• Neurons in range of each other share a synapse. Touch, feed, startle or pick one up and it fires, and the pulse travels the chain hop by hop. Arrival wakes anything dormant standing nearby and makes everything else flinch. Lay six in a line and you have built a circuit; lay them in a ring and it runs on its own.
• Algae feed themselves from the lamp and quietly make spare nutrients for everyone else. A dish with algae in it never fully starves.
• Amoebas are enormous and barely hold their shape — the floppiest body in the dish. When peckish they engulf small invaders whole.
• Tardigrades trundle about on eight stubby legs and burn energy at a quarter of everyone else's rate. Push the dials far enough to kill everything else and they curl into a tun — a rigid barrel that ignores every condition in the panel and cannot be killed at all. Put the dials back and it unrolls, blinks, and carries on.
• Mitochondria are the powerhouse. They latch onto the nearest larger cell and pump energy into it down a glowing tether.

Odd bodies

The second tray. Nothing here has a number key — click the icon, then click the agar.

• Slime moulds ooze about laying down a scent trail, and everything else in the dish would rather walk on a trail than break new ground. Leave two or three running and a road network draws itself.
• Yeast never splits down the middle. It pinches one small copy off its flank, keeps its own name, and adds another bud scar. It also burps.
• Paramecia do not steer. They pick a heading, commit to it entirely, hit something, and about-face.
• Rotifers run a spinning wheel of cilia that drags loose food in from right across the neighbourhood.
• Diatoms are glass. They do not move, they barely burn anything, and they are only here to be looked at.
• Stem cells have blank faces and no plans. They keep score of whoever they touch and eventually become that — keeping the name they arrived with.
• Vorticellae are bells on coiled stalks, stuck to one spot on the glass. Startle one and the coil fires shut in a single frame, then takes three slow seconds to wind back out. Nothing else in the dish is spring-loaded.
• Heliozoans never chase anything. They sit still behind a ring of rigid glass spokes, and whatever brushes a spoke is held there and quietly digested. The dish's only ambush.
• Copepods hop. They gather, pause, and launch — nothing else in here moves in bursts. Hold one and it winds up; let go and it fires off across the dish.
• Bacteriophages hunt bacteria, set down on one like a lunar lander, and drain it. The host bursts into more phages. You can grab a phage and pull it straight off its host, and a white cell will pop one that is standing still. It is also the only thing in the dish with no real face: two flat dots that never blink and never look at you.

Meet the invaders

• Viruses seek pink body cells. If an infection completes, the cell releases new viruses.
• Bacteria flee white blood cells and may split into two if they survive long enough.

Grabbing cells

Every cell is a real soft body: a ring of point masses held together by springs and internal pressure. With the Grab tool, press on a cell and the nearest bit of its membrane follows your pointer, so it stretches like jelly and springs back when you let go. Drag one into a crowd and the whole dish reshuffles.

Panels & physics

The tools, conditions and lab panels all float over the dish. Drag them anywhere by their body, or tap the − button to shrink one out of the way. The View menu brings back anything you have folded up.

The Tank row swaps the backdrop the whole stage is drawn on: the default petri dish, sage graph paper, a drafting blueprint, a bright microscope slide, or a charcoal dot field. Your choice is remembered between visits.

Controls

Keyboard shortcuts

• A – Grab tool.
• F – Feed tool.
• Q – Place tool.
• X – Remove tool.
• S – Stirring rod.
• E – feed everyone at once.
• 1–9, 0 – pick a specimen.
• ↑↓←→ – lean the dish.
• Space – pause or play.
• Ctrl/⌘ + Z – undo.

Things to try

• Place a virus near a body cell, then send in a platelet.
• Build an immune squad of white cells before adding invaders.
• Put two neurons within reach and watch the signals travel.
• Sprinkle protein on one body cell until it divides, then keep going and watch the dish fill up.
• Push Appetite to 100%, walk away, and come back to a dish full of snoring cells. Then feed everyone.
• Drop a lone algae in an empty dish and let it stock its own pantry.
• Pour sugar on a tardigrade and watch it sprint on its little legs.
• Pause the dish to arrange a scene, then press play.
• Drop Turgor to 0% and Stiffness to 10%, then drag a cell — it goes completely floppy.
• Plate the Mat preset and leave it alone for two minutes, then look at the roads the slime moulds have worn in.
• Slide Salinity to Rain water and watch every cell in the dish swell. Then take it to Brine and watch them all shrivel.
• Turn the Light off entirely with an algae-only dish. Nothing eats, everything sleeps. Turn it back up and the pantry restocks.
• Take the Temperature to Frozen and everyone slowly shuffles into one shivering huddle.
• Pour caffeine on a paramecium. It was already the fastest thing in the dish.
• Drop a stem cell into a crowd of one species and wait for it to make up its mind — the ring around it fills in the colour it is leaning toward.
• Sprinkle glow dye, then take the Light down to nothing. The dish goes dark except for whoever ate.
• Hold an arrow key to pour the whole dish into one corner, then let go.