Every pixel here holds a number from 0 to 255, never a colour. The 256 colours live in a table, and the picture moves only because the table changes: ranges of it rotate (the waterfall, the lake, the smoke, the stars, the fireflies), and the whole of it is re-lit for the hour. Nothing is redrawn. That is colour cycling, the technique of Mark Ferrari's painted game scenes, which Joseph Huckaby's Canvas Cycle brought to the browser.

The sky is real. Choose a place, a date and the way the painting faces, and the stars stand where they stand there and then (2851 of them, to magnitude 5.5, from the Hipparcos-based catalogue of d3-celestial), the moon rises in its true phase, and the sun's path painted into the sky is that day's track. The sky is drawn as a stereographic projection, so the constellations keep their shapes.

The music is composed as it plays, for this landscape and this moment, and played on John O'Laughlin's physically modelled piano and guitar (pfsynth), rendered as you listen. The biome sets the key and its character (the canyon is flamenco), the light sets how bright the mode is, and where you are sets the texture: pedalled arpeggios at the lake, a guitar tremolo at the falls, an ostinato by the river, rolled chords on the mountains, harmonics under the stars. It never ends and never repeats, and every note lights something.

And the world can be flown. Press fly: the painting's world is built in three dimensions, every patch of ground still a palette index (what it is, and which way it faces), drawn the way Comanche drew in 1992, Voxel Space, column by column. The flight is a loop: over the lake, up the face of the falls, along the river, round the mountains and down past the cabin, once every five days of the scene's clock.

The weather is a forecast for the place and the moment. Each day draws its kind, weighted by the season: clear, fair, overcast, rain, storm, fog or snow, and whether what falls is rain or snow depends on a temperature from the date, the latitude and the hour. Showers come and go, storms build in the afternoon, fog lies in the valley at dawn, and snow that fell stays on the ground while it is cold. Overcast hides the sun and the moon and greys the light, the lake rings where the rain lands, lightning whitens everything for an instant, and its thunder arrives as late as the strike was far, in the rain and wind of the beds and as a low cluster on the piano. The music turns with it too. Or choose the weather yourself.

Or the coast. A beach on the open sea, a headland with a lighthouse, boats under sail and gulls overhead. The surf is two colour cycles turning together: one rolls the lines of breakers in across the shallows, and the other runs the foam up the sand and leaves it wet behind, so the wave that breaks is the wave that washes up. Each wave takes two bars of the music, and you hear it break as you see it. At night the lighthouse turns, and its beam is a fan of palette colours lit in turn.

Or a city. Press city and the flight is a town seven centuries deep: country lanes that became its old roads, a walled core, a Georgian grid, a boulevard scheme, suburbs, modern slabs and glass towers, each building rebuilt or left standing as its land rose in value, on hills with a river through them. Every wall is drawn row by row from the building's period, so a storey is a storey and a bay is a bay: sash windows in brick, timber frames, balconies along the stone apartment blocks, ribbon windows, curtain walls. Each window is one of sixteen households, dark glass by day; at night each lights when it is dark enough for it, and the sixteen turn slowly, so lights come on and go off across the city. You fly down the river between the quays with the city standing in it, up over the old core, along an old road at the height of its eaves, and up round the towers.

And the aurora, where a place would see it. Every night has its own geomagnetic weather, so Tromsø or Reykjavík see curtains on most dark nights, New York only in a storm and then low and red in the north, and Sydney toward the south. Each direction in the sky is traced out to curtains standing 100 to 300 km up: oxygen's green low down, red above, rays drifting along the folds, mirrored in the water. Choose "aurora storm" under sky for a big night.

Here the scene is generated for the palette. Water is painted in phase, so turning its colours pours it. Rock is painted by the way each face turns, so the shadows swing across the mountains as the sun crosses. The sun's path is painted into the sky as a row of discs, one colour each, and lighting one is the sun; the lake carries a glitter path under the sun or the moon. The music keeps the palette's beat, takes its mode from the light, and every bell lights a star.