Who really needs a “You Are Here” marker when other visitors’ fingers have done the work for you? (Above, in Florence; below, in San Francisco)

Use-marks, like desire paths, are a kind of emergent behaviour record of previous users’ perceptions (and perceived affordances), intentions, behaviours and preferences. (As Google’s search history is a database of intentions.) Indeed, while we’d probably expect the “You Are Here” spot to be worn (so it’s not telling us anything especially new) can we perhaps think of use-marks / desire paths as being a physical equivalent of revealed preferences? (Carl Myhill almost makes this point in this great paper [PDF].) And (I have to ask), to what extent does the presence of wear and use-marks by previous users influence the use decisions and behaviour of new users (social proof)? If you see a well-trodden path, do you follow it? Do you pick a dog-eared library book to read because it is presumably more interesting than the ones that have never been read? What about where you’re confused by a new interface on, say, a ticket machine? Can you pick it up more quickly by (consciously or otherwise) observing how others have worn or deformed it through prior use? Can we design public products / systems / services which intentionally wear to give cues to future users? How (other than “Most read stories today”) can we apply this digitally?

In a similar vein to the Mosquito, intentionally shallow steps (and, superficially at least–though not really–blue lighting in toilets, which Raph d’Amico dissects well here), we now have residents’ associations installing pink lighting to highlight teenagers’ acne and so drive them away from an area: Residents of a Nottinghamshire housing estate have installed pink lights which show up teenagers’ spots in a bid to stop them gathering in the area. Members of Layton Burroughs Residents’ Association, Mansfield say they have bought the lights in a bid to curb anti-social behaviour. The lights are said to have a calming influence, but they also highlight skin blemishes. The National Youth Agency said it would just move the problem somewhere else. Peta Halls, development officer for the NYA, said: “Anything that aims to embarrass people out of an area is not on. “The pink lights are indiscriminate in that they will impact on all young people and older people who do not, perhaps, have perfect skin. I had heard about this before (thanks, Ed!) but overlooked posting it on the blog - other places the pink lights have been used include Preston and Scunthorpe, to which this quote refers (note the youths=yobs equation): Yobs are being shamed out of anti-social behaviour by bright pink lights which show up their acne. The lights are so strong they highlight skin blemishes and have been successful in moving on youths from troublespots who view pink as being “uncool.” … Manager Dave Hey said: “With the fluorescent pink light we are trying to embarass young people out of the area. “The pink is not seen as particularly macho among young men and apparently it highlights acne and blemishes in the skin. … A North Lincolnshire Council spokesman said: “[...]“On the face of it this sounds barmy. But do young people really want to hang around in an area with a pink glow that makes any spots they have on their face stand out?” With the Mansfield example making the news, it’s good to see that there is, at least, quite a lot of comment pointing out the idiocy of the hard-of-thinking who believe that this sort of measure will actually ’solve the problem of young people’, whatever that might mean, as well as the deeply discriminatory nature of the plan. For example, this rather dim (if perhaps tongue-in-cheek) light in the Nottingham Evening Post has been comprehensively rebutted by a commenter: Trying to use someone’s personal looks against them simply because they meet up with friends and have a social life… If this is the case then I would personally love to see adults banned from meeting up in pubs, parties and generally getting drunk. I would also love to see something making fun of their elderlyness and wrinkle problems. I don’t understand why Britain hates its young people so much. But I can see it storing up a great deal of problems for the future. Photo from this BBC story

We can’t help but be familiar with the concept of ‘malicious code’ in the context of computer security and programming, but in general the idea of products or technology which, as they’re used, sabotage or degrade the performance of a ‘rival’, is intriguing and not well-explored. Scott Craver’s Underhanded C contest is a fascinating example from the ‘white hat’ side of the fence; Microsoft’s use of deliberately targeted style sheets on MSN.com to degrade Opera’s performance is another; and the CIA’s alleged planting of software bugs in Russian pipeline control software is a third. The Sony DRM rootkit might also fall into this category (as would this!) But on a much more concrete level, we have this playful example: Memoires by Guy Debord, psychogeographer and Situationist, was originally published with a rough sandpaper cover: Memoires was written, or rather assembled, by Guy Debord and Asger Jorn in 1957. Debord himself often referred to Memoires as an anti-book, and the original edition was bound in sandpaper, that it might destroy other books. The text is entirely composed of fragments taken from other texts: photographs, advertisements, comic strips, poetry, novels, philosophy, pornography, architectural diagrams, newspapers, military histories, wood block engravings, travel books, etc. Each page presents a collage of such materials connected or effaced by Jorn’s structures portantes, lines or amorphous painted shapes that mediate the relationships between the fragments. (from an article by David Banash)

And from this article by Christian Nolle: The book is most famous for its sandpaper cover. An auto-destruction feature that enabled it to damage not only the book it might be standing next to in the bookshelf, but also the person who would be reading it. An anti-book to destroy all other books. Permild writes: “Long had he [Jorn] asked me, if I couldn’t find a unconventional material for the book cover. Preferably some sticky asphalt or perhaps glass wool. Kiddingly, he wanted, that by looking at people, you should be able to tell whether or not they had had the book in their hands. He acquiesced by my [Permild’s] final suggestion: sandpaper (flint) nr. 2: ‘Fine. Can you imagine the result when the book lies on a blank polished mahogany table, or when it’s inserted or taken out of the bookshelf. It plans shavings of the neighbours desert goat [?]’. In all the literature that I have located, Debord is the person who is refered to as the inventor of the sandpaper cover. However, as it turns out Debord had nothing to do with it… Permild continues, «Asger loved - as he often expressed it, to place small time controlled bombs». This was certainly a bomb. A bomb invented by the printer, whose job is normally of a technical nature. The sandpaper cover was a really good idea, but practically it never managed to practice what it preached. It did, however, make its readers conscious about handling it or where to place it. One the other hand, Memoires placed itself on a shelf among precious object, something to be handled with great care… The American Hakem Bey did something similar in the 1970s. In homage to Guy Debord, Bey made a book with sandpaper on the inside. This way he rendered the book into auto-destruct mode if you would ever dare to read it. A potential bomb to go off if you would open it. Memoires, on other hand is a bomb, not a potential bomb. No matter how you would handle it, there was always the danger that it could damage your precious collection of 1920s French poetry. The photos above come from this French eBay listing - the copy on sale reached €3,810.