Tide pool

Everything here is one surface: a rocky shore that the tide floods and drains every four minutes. The water is simulated: as the tide rises the sea comes in over the rock, up the gullies first, and pours over the lip of the pool; as it falls it drains away again. A swell rolls in off the sea all the while, and its waves break into foam on the rocks, bigger in a storm. The surface is simulated too, a few centimetres at a time: every drop, swimmer and gust of wind raises ripples that spread, interfere, and bounce off the rock, and the sunlight they bend gathers into the bright, shifting net on the floor of the pool, while the floor itself, seen through them, sways as they pass. Loose sand lies in the hollows and gullies and wherever the borers heap their spoil; fast water lifts it and slow water lets it fall, so the gullies scour, spoil heaps wash out, and a storm rearranges the shore. The tide's reach swells and shrinks with the moon, which waxes and wanes over forty minutes: springs come at full and new moon, so some low waters lay the shore bare, and the rock stays dark and glistening where the water has just left it. Full-moon nights are silver; on moonless nights the plankton, the stars in still water, and the lit windows show best. Wherever the ground dips and cannot drain as the tide falls, water stays behind, and that is a pool. The shelf you arrive on has been going for a few tides: the borers have dug, an artificer has put up a structure in the first pool, and the others arrive in their time. Borers dig burrows and tunnels, masons fill hollows and raise walls, and breakers knock walls down, so the pools grow, join, drain, and form on their own. Pools are named as they appear. Artificers build structures in the water out of small parts, one at a time, each chosen from what is already around it: frames that bear load, solid plates, decks that reach out over the water, pods to live in, gears and tide wheels the tide turns, pipes, and lamps. Nothing is planned beyond the next part, so no two structures come out alike. A structure's footing is solid: the water goes around it, and the ground under it holds. Scrapers sleep in the pods, collectors keep hoards on the decks, and the tabs circle below and dart in among the frames when something startles them. Breakers work parts loose at the footing and artificers make them good again; when a footing gives way, everything it held falls. A tide wheel on a structure turns only while the water runs through it and stores its charge; the structure's lamps and windows burn at night only with a charged wheel nearby. Artificers also build working machines: a sluice gate on a pool's outlet shuts as the tide falls and holds the pool full, and a beacon, powered by a wheel, burns at night, feeds the plankton around it, and draws the tabs. Now and then a storm comes in off the sea: the water rises and runs rough, the waves batter whatever stands at the waterline, and the fish hide among the frames. Day turns to night every seven minutes, and the film on each floor grows only in wet light. At night the plankton glows wherever something moves through it.

• SC Scraper. Creeps slowly over wet floors, grazing the film as it goes, and leaves clean trails through it. Hides in shells, hollows, and walled homes, and sleeps in a pod up in a structure.
• TB Tab. Schools in open water, turning as one, and makes its home circling a structure, darting in among its frames when startled. Follows the plankton when hungry. Ranges out over the flooded shore at high water and swims home to its pool as the tide turns.
• PY Pylon. Stands still, filters the water, and catches tabs. Buds settle at the foot of structures.
• CL Collector. Salvages husks and hoards brass in a corner, or up on a structure's deck.
• MS Mason. Fills. Lifts spoil and stones and builds walled homes, filling in the hollow beneath first.
• BR Breaker. Hunts scrapers. Breaks walls down to reach them, and tears at a structure's footing to bring a pod down.
• BO Borer. Digs. Sinks a burrow, then tunnels outward toward other water and banks the spoil beside it.
• AR Artificer. Builds from brass and salvage: structures in the water, one small part at a time, and sluice gates and beacons. Each has its own way of building, which its children inherit. Mends parts that breakers and storms work loose.

Large machines need a brass core to cast a new body. When they stop, they leave a husk and give their core back. Brass, shells, and pebbles also wash in from the sea at high tide. Collectors hoard it, and others steal it.

Tap a machine to follow it. Choose a material, then tap water to drop it. Feed makes the film and plankton bloom where it lands. After dark every machine's lamp is lit, so the life on the shelf shows as small moving lights, and a ball of light floats wherever you point, over rock or water, lighting what is around it and casting shadows; the fish come to it, and the plankton sparks behind it as you move it over the water. Drag to look around, pinch or scroll to zoom, and twist two fingers or right-drag to turn the view; the compass turns it back. Double-tap to zoom in on a spot. Leave it alone and the controls fade away and the view drifts on its own toward whatever is happening, unless you turn that off in Settings; any touch brings them back. Every visit grows its own shelf; its number is in the address, so you can send someone yours, and Begin again grows another. A purely synthetic, procedural artwork. Sound is optional and starts only when you turn it on. Your settings stay in this browser; nothing else you do here is saved, and nothing is sent.

Keyboard: the keys work anywhere on the page. Hold W, A, S, or D to glide the view, Q or E to turn it, and R or F to zoom, with Shift to go faster. Z and X choose what to drop, and Space or Enter drops it where you point. Arrow keys move the marker; Shift and arrows pan. Plus and minus zoom. Brackets step between machines. Escape releases. Keys 1 to 9 jump to a pool. Question mark lists the keys. Reduced-motion settings start the world paused; you can choose to play.

Rendered with Three.js. Software license.