Unknown Pleasures

Aa pulsar

The plot as on the sleeve, 80 pulses, playing: a new one arrives at the front every 1.337 seconds and the oldest leaves at the back, so the whole plot is replaced every 107 seconds.

Point at a line to light its pulse; with sound, each pulse clicks as it arrives.

Bb ripple

A pond seen at a slant, each line a row of its surface. A stone dropped in sends rings out, which bounce off the banks and die away. Left alone, a drop falls now and then.

Click to drop a stone; drag through the water.

Cc flight

Flying up a valley between mountains, the land drawn as the plot is: ridges from the horizon down, each hiding what is behind it, the farther ones closer together. Left alone, it follows the valley; steered into a mountain, it climbs over it.

Point to steer: to either side to turn, higher up to climb. Press to fly faster.

Dd word

Words raised out of the lines, a low relief seen at a slant: where the letters lie, the rows rise. They can be set in the page's own roman letters or in blackletter, the angular letters of German printing from Gutenberg's Bible on. From straight above the lines lie flat and the words are gone; from the side, only their skyline is left.

Type, pick the lettering, then move across it.

Ee voice

The microphone as the telescope: each new line is what it hears at that moment, split by pitch, the lowest in the middle and higher ones further out on both sides, so a voice rises where the pulse does. Nothing it hears leaves the page, and it turns off when the drawing scrolls away.

Press to listen, then hum or speak; press again to stop.

Ff record

The pulses wound round as a record's grooves, each ring hiding the rings outside it where it rises. It turns at 45 rpm, once every 1.333 seconds, within a third of a percent of the pulsar's 1.337, and the stylus works inward a ring a turn. With sound, the stylus plays the groove under it, loud where the groove rises: the sky's hiss, the pulse thumping past once a turn, and now and then dust, all higher and louder the faster it turns.

Turn sound on to hear it play; drag it round to scratch it, and let go for the motor to bring it back up to speed.

Gg plotter

The plot drawn again by a pen whenever a setting changes, as a pen plotter would have to draw it: a pen cannot paint over a line, so it starts with the nearest pulse and draws each one further back only where it rises above everything drawn so far. The settings: how many pulses, how high a pulse rises, how loud the sky's noise is, and how far each pulse's sub-pulses sit along from the last one's, as CP 1919's drift.

Hh fold

Each line is one of the pulsar's periods, drawn left to right as it passes, its pulse in the middle; a tap marks the line where the pen is. Tapped on the beat, the marks stack into a column over the pulses; early or late, they lean. Astronomers line a pulsar's pulses up the same way, cutting a recording into lengths of its period and laying them one on another.

Tap in it as the pen crosses the middle; with sound, the pulsar clicks there and each tap ticks.

Ii mirror

The camera as the telescope: the lines rise where the picture is bright, a relief seen from in front and a little above, so a face shows as its light falls on it. Where the picture moves the lines leap up and settle back, so a wave of the hand ripples through them. Nothing it sees leaves the page, and it turns off when the drawing scrolls away.

Press to turn the camera on; press again to stop.

Jj psychedelic

The plot in colour: each line filled with a run of colours across it, the colours turning as they roll down the stack, while a swell passes down through the pulses and they sway from side to side. A click sets a little organism down there: it throbs, each beat sending a ring out through the lines and flashing the colours round it, and after a few seconds it fades.

Move across it to turn the colours; click to set an organism down.

Kk marbles

A marble dropped falls onto the first line below it and rolls down into the dips beside the pulses, where it settles, hidden wherever a nearer line rises in front of it. Off the end of a line, it falls away.

Click to drop marbles.

Ll tunnel

Flying down a tunnel whose rings are pulses bent into circles, each turned a little further than the last so the pulses wind along it. A ring hides the farther ones where its pulse reaches in. Left alone, it follows the bends. With sound, it hums the nearest ring's pulse, the pulse's shape as the shape of the hum's wave, swelling as each ring passes and higher the higher you fly.

Point to steer, press to fly faster; with sound, it hums each ring as you pass.

Mm snow

Snow falls between the lines and settles on the one it meets, sliding off wherever it lies steeper than it holds, so the valleys fill and the pulses soften. It melts slowly.

Move across it to blow the snow off.

Nn binary

The rubber-sheet picture of gravity: two stars in orbit, each a dent in the sheet, sending out ripples that wind away from them as they go round. The ripples carry energy off, so the stars draw closer and circle faster until they meet; a while later a new pair starts. In 1974 a pulsar was found in such an orbit, PSR B1913+16, and its orbit shrinks at the rate gravitational waves carrying energy away would give. With sound, it plays the waves' tone, at twice the orbit's rate as the waves have it, scaled up 80 times to be heard: it rises and grows louder as the stars close in, the chirp the LIGO detectors first picked up in 2015, from two black holes merging.

Click to start a pair there; with sound, it chirps as they close in.

Oo nave

A walk down a cathedral nave whose arches are pulses: each arch's opening is a pointed arch with a pulse along its edge, its peaks hanging from the arch's point like carved stone, and each arch hides the ones behind it where its pulse reaches in. At the far end a rose window turns, its rings pulses too, and it stays as far off however long you walk. With sound, an organ plays a chord as each arch passes, the shape of its pipes' wave the shape of that arch's pulse, echoing as in a stone hall.

Point to look round, up into the vault and down; press to walk faster.

Pp animals

The plot as on the joke shirts, Black Milk's Shark Division and Meow Division: the pulses become animals crowding the middle of the stack, where the pulses stand, with a few strays at the sides. Sharks pace to and fro, now and then sinking to the fin; cats peek up over the lines, their eyes on the pointer; rabbits hop; bats flap; sea serpents swim with humps running along their backs. An animal's back is its line, so it hides the lines and animals behind it as a pulse would.

Pick the animals; point to bring them up, or click to bring one up there.

Qq pelican

The drawing Simon Willison asks of each AI model he tries, a pelican riding a bicycle, raised out of the lines as the words are in Dd. It pedals on the spot while the dashes of the road run back under its wheels.

Press to pedal faster.