Stacking rubbish bags against a wall. Slide a bag over the heap, turn it, and let it go — it drops, slumps onto what is under it, and either holds or slides off. The dotted lines are the floors of the building behind it; a heap that climbs past one is bags reaching a window.

The basket is the goal, and it runs the opposite way from the height above it. A basket hangs from a rope somewhere overhead — follow the line up to find where — the way a Neapolitan window still lowers one on a string today, a panariello, for anything too far to carry up the stairs. Build until a bag that has come to rest reaches it: the bag is taken away rather than added to the heap, one more collected, and the next basket hangs higher, and rarely over your pile, so the stack has to lean or start again somewhere else. A bag still slumping does not count — it has to hold.

Naples once did this for real, and not by choice. On 21 December 2007 rubbish collection stopped across Campania because every landfill in the region was full. Within weeks around 100,000 tonnes of waste sat in the open — roughly 6,000 tonnes in the streets of Naples itself and another 50,000 along the roads of the region — and in the narrow alleys of the old city the bags piled up to the first-floor windows. It was not a one-off: Campania had been under a formal waste state of emergency since 1994.

Underneath it was the Camorra, which ran the whole disposal cycle — the trucks, the dumps, the businesses — and for years buried toxic and industrial waste in illegal sites north of the city, then set the overfilled tips alight. That stretch became known as the Terra dei Fuochi, the Land of Fires. Naples makes about 1.6 million tonnes of rubbish a year; in July 2008 the army was sent in to clear the streets, and 700 tonnes a day were shipped off to be burned in Hamburg while the heaps were carted away.

So a pile that reaches the storeys is not really a score — the basket is. It is what a city looks like the moment the cycle that carries its waste away stops turning, and the basket is that cycle starting again: every bag it takes is one that never reached the first-floor windows. Here you build the heap yourself, and the only way to bring it back down is to feed the rope instead.

Mouse drags a bag, a finger points — drag sideways over the heap to aim, the wheel or the slider turns it. Nothing is saved and nothing leaves the page. Sources: Wikipedia, Naples waste management crisis; NPR and CNN reporting, January 2008.