Instructions: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Input: City doubles number of walls that spray back 
  
 To all the late-night revelers who answer nature’s call on city walls: Beware. Again. 
  
 The Public Works Department is doubling the number of walls painted with pee-repellent paint. In July, DPW installed nine in the Tenderloin, the Mission and South of Market. Eight more will be added this week. The surfaces make urine bounce right back onto the shoes and pants of unsuspecting relief-seekers. And, so far, it seems to be working. 
  
 “So far so good,” Public Works Director Mohammed Nuru said. “We have had a daily monitoring program, and it seems to be 95 percent successful. There’s only one alley in the Mission that we have had trouble with.” 
  
 The monitoring system consists of one lucky individual conducting a smell and sight test — anything that smells putrid or looks moist is noted. The trial period for the pee wall program ends in December, and the city will assess its effectiveness then. 
  
 But it’s already been proved to work in Europe. The paint was first used in Hamburg’s St. Pauli quarter, where beer drinkers often can’t be bothered to find a bathroom. The experiment captured the attention of San Francisco officials. 
  
 Historically, public urination has been an issue in San Francisco. Legislation banned it in 2002 but that really didn’t work, despite the threat of a $50-to-$500 fine. The Pit Stop program, which provides public restrooms, has contributed to a 17 percent drop in steam cleaning requests since last summer. But city officials wanted to do more. 
  
 “It went really well in Hamburg,” Nuru said. “Based on that, I think this program is really going to work. It should deter people.” 
  
  
  
  
  
  
  
  
  
  
  
  
  
 Photo: Scott Strazzante, The Chronicle Image 1 of / 4 Caption Close Image 1 of 4 Buy photo Wayne Howard stands in the corner by a wall that has been coated with pee-repelling paint at the 16th and Mission Street Bart Plaza in San Francisco, Calif., on Thursday, July 30, 2015. Wayne Howard stands in the corner by a wall that has been coated with pee-repelling paint at the 16th and Mission Street Bart Plaza in San Francisco, Calif., on Thursday, July 30, 2015. Photo: Scott Strazzante, The Chronicle Buy this photo Image 2 of 4 Buy photo Two walls have been coated with pee-repelling paint at the 16th and Mission Street Bart Plaza in San Francisco, Calif., on Thursday, July 30, 2015. Two walls have been coated with pee-repelling paint at the 16th and Mission Street Bart Plaza in San Francisco, Calif., on Thursday, July 30, 2015. Photo: Scott Strazzante, The Chronicle Buy this photo Image 3 of 4 Using the wall at 16th Street and Mission as an example, Public Works director Mohammed Nuru demonstrates how the walls deflect liquid onto the clothes of those that urinate on the walls. Using the wall at 16th Street and Mission as an example, Public Works director Mohammed Nuru demonstrates how the walls deflect liquid onto the clothes of those that urinate on the walls. Photo: Cameron Robert, The Chronicle Image 4 of 4 Using the wall at 16th Street and Mission as an example, Public Works director Mohammed Nuru demonstrates how the walls deflect liquid onto the clothes of those that urinate on the walls. Using the wall at 16th Street and Mission as an example, Public Works director Mohammed Nuru demonstrates how the walls deflect liquid onto the clothes of those that urinate on the walls. Photo: Cameron Robert, The Chronicle City doubles number of walls that spray back 1 / 4 Back to Gallery 
  
 Signs over the walls read, “Hold it! This wall is not a public restroom. Please respect San Francisco and seek relief in an appropriate place.” They don’t explicitly state that the wall will fire back, so some surprises are in store for the unwitting relief-seeker. 
  
 Paint and installation costs a couple of hundred dollars for each wall. The coating, Ultra-Ever Dry, comes from Ultra-tech, a Florida company in the chemical cleanup and waste management business that also provided the paint for Hamburg. 
  
 The paint coats an object and creates a surface chemistry and texture with patterns of geometric shapes that have peaks, or high points, that repel most water-based and some oil-based liquids. 
  
 If it continues to work, even more walls will be painted around the city. 
  
 Lizzie Johnson is a San Francisco Chronicle staff writer. E-mail: ljohnson@sfchronicle.com Twitter: @lizziejohnsonnn ||||| If it’s not winter’s salt and grime, it’s mud and everyday dirt. Keeping your car clean can be a chore – a backbreaking one if you prefer to do it yourself. 
  
 But Nissan is testing a car that can keep itself clean, thanks to special paints that repel water and oils. Similar technology could eventually allow manufacturers to do away with windshield wipers by effectively fending off water, frost and grime. Meanwhile, new coatings can also help keep a car’s interior cleaner, something especially useful for parents – or those actively involved in sports like camping and trail biking. 
  
 The Nissan Technical Center in Rolle, Switzerland, is in the midst of testing a specially prepared version of the maker’s little European Note model. The subcompact hatchback has had a layer of a special coating, called Ultra-Ever Dry, applied over its conventional paint finish. Developed by UltraTech International, it’s technically known as a super-hydrophobic and oleophobic paint. In other words, it actually repels both oil and water. 
  
 That means that most common dirt, grime and oil won’t stick to the vehicle’s sheet metal. The Ultra-Ever Dry finish even works with rain, frost and sleet, Nissan reports, after preliminary testing. 
  
 "The Nissan Note has been carefully engineered to take the stress out of customer driving,” said Geraldine Ingham, the chief marketing manager for the hatchback. "We are committed to addressing everyday problems our customers face and will always consider testing exciting, cutting edge technology like this incredible coating application." 
  
 Nissan is testing a version of its Note subcompact, which has a layer of a special coating to make it repel water and oil. Nam Y. Huh / AP 
  
 For the moment, the maker says it has no plans to offer the coating as a standard feature, but “will continue to consider (it) as a future aftermarket option.” 
  
 The maker did come up with another interesting paint technology a few years back, a self-healing paint. Dubbed Scratch Shield, it uses an elastic resin mixed into a conventional paint formulation that, when exposed to sunlight, would fill in small scratches within a matter of hours. Unfortunately, few motorists have been willing to pay the premium for the special formulations and Nissan now offers Scratch Shield in only a few markets and not the U.S. 
  
 The Japanese maker isn’t the only one looking at hydrophobic coatings – which could prove an interesting alternative for keeping windshields clear and clean. Italian designer Leonardo Fioravanti recently rolled out a wiper-less Hidra concept vehicle, which relies on both aerodynamic design to minimize what actually comes close to the windshield – and a special coating designed to keep things from sticking if they do come into contact with the glass. 
  
 Under a hydrophobic outer coat, a second, nano layer “pushes” dirt off to the sides, while a third layer essentially helps clean off grime. An additional, electrically conductive layer provides the power needed to make it all work. 
  
 The designers claim the technology behind the Hidra wiper-less windshield could prove reasonably cost-competitive and could wind up in production in a few years, marking the most significant improvement in rain gear since the first hand-operated wipers were introduced more than a century ago. 
  
 British sports car maker McLaren, meanwhile, has lifted a page from fighter jet construction. It is experimenting with a system that uses high-frequency sound waves to create a sonic barrier to prevent water and dirt from reaching the windshield. 
  
 Cleanliness is only one reason makers would like to eliminate the windshield wiper. The devices also create plenty of aerodynamic drag, which reduces a vehicle’s fuel economy. 
  
 Manufacturers also are looking at ways to keep things clean inside their vehicles. Most fabrics are now treated with dirt- and liquid-resistant coatings – or can be ordered with an optional treatment package. Ford says it also tries to design vehicles so it’s easy to wipe or vacuum food or spilled beverages out of cracks and crevices. 
  
 And to that effect, the new Honda Odyssey minivan this year began offering an optional, built-in vacuum cleaner tucked into its rear cargo compartment. 
  
 Of course, one challenge is to prevent messes in the first place, says General Motors, which has been conducting research on ways to keep passengers, especially children stuck in back seats known to industry engineers as “the puke zone,” from getting car sick. 
  
 “We know through other scientific research that even if our eyes are focused on a fixed point – if we can see the outside passing by in the window – our brain is telling us that we are moving,” explained Don Shreves, GM’s Human Factors engineering group manager said. “But if our eyes are at a downward angle and do not see the view outside the vehicle, our bodies become sensitive to motion and increase the chance of sickness.” 
  
 Among other things, the research has shown GM engineers that passengers are less likely to get sick when DVD screens are mounted overhead. |||||
Output:
San Francisco's experiment with pee-repelling paint is working out so well that the city says it will expand the trial in an attempt to prevent further public urination. Since treating nine of its walls with a liquid-repelling coating that causes urine to bounce back at anyone seeking relief, the city has been sending an unfortunate individual to smell the city's walls and look for moist areas. "So far so good," says Public Works Director Mohammed Nuru. "We have had a daily monitoring program, and it seems to be 95% successful," though he adds there's one particular alley "that we have had trouble with." As a result, officials will apply the Ultra-Ever Dry paint from Florida company Ultra-tech to eight more walls this week, reports the San Francisco Chronicle. Once the program's trial period wraps in December, city officials will review the effectiveness of the paint, which has worked "really well" in Hamburg, Germany, says Nuru. "Based on that, I think this program is really going to work. It should deter people." Signs on the coated walls state: "Hold it! This wall is not a public restroom. Please respect San Francisco and seek relief in an appropriate place." But as they don't explain that the texture produced by the paint creates peaks that repel most water-based and some oil-based liquids, "surprises are in store for the unwitting relief-seeker," notes the Chronicle. Last year, NBC News reported Nissan was testing a vehicle coated with Ultra-Ever Dry paint, meaning soon you may never have to wash your car again. (San Francisco should probably add the stuff to its light poles.)