A computing platform or digital platform is the environment in which a piece of software is executed. It may be the hardware or the operating system a web browser and associated application programming interfaces, or other underlying software, as long as the program code is executed with it. Computing platforms have different abstraction levels, including a computer architecture, an OS, or runtime libraries. A computing platform is the stage. A platform can be seen both as a constraint on the software development process, in that different platforms provide different functionality and restrictions. For example, an OS may be a platform that abstracts the underlying differences in hardware and provides a generic command for saving files or accessing the network. Platforms may include: Hardware alone, in the case of small embedded systems. Embedded systems can access hardware directly, without an OS. A browser in the case of web-based software; the browser itself runs on a hardware+OS platform, but this is not relevant to software running within the browser.
An application, such as a spreadsheet or word processor, which hosts software written in an application-specific scripting language, such as an Excel macro. This can be extended to writing fully-fledged applications with the Microsoft Office suite as a platform. Software frameworks. Cloud computing and Platform as a Service. Extending the idea of a software framework, these allow application developers to build software out of components that are hosted not by the developer, but by the provider, with internet communication linking them together; the social networking sites Twitter and Facebook are considered development platforms. A virtual machine such as the Java virtual machine or. NET CLR. Applications are compiled into a format similar to machine code, known as bytecode, executed by the VM. A virtualized version of a complete system, including virtualized hardware, OS, storage; these allow, for instance, a typical Windows program to run on. Some architectures have multiple layers, with each layer acting as a platform to the one above it.
In general, a component only has to be adapted to the layer beneath it. For instance, a Java program has to be written to use the Java virtual machine and associated libraries as a platform but does not have to be adapted to run for the Windows, Linux or Macintosh OS platforms. However, the JVM, the layer beneath the application, does have to be built separately for each OS. AmigaOS, AmigaOS 4 FreeBSD, NetBSD, OpenBSD IBM i Linux Microsoft Windows OpenVMS Classic Mac OS macOS OS/2 Solaris Tru64 UNIX VM QNX z/OS Android Bada BlackBerry OS Firefox OS iOS Embedded Linux Palm OS Symbian Tizen WebOS LuneOS Windows Mobile Windows Phone Binary Runtime Environment for Wireless Cocoa Cocoa Touch Common Language Infrastructure Mono. NET Framework Silverlight Flash AIR GNU Java platform Java ME Java SE Java EE JavaFX JavaFX Mobile LiveCode Microsoft XNA Mozilla Prism, XUL and XULRunner Open Web Platform Oracle Database Qt SAP NetWeaver Shockwave Smartface Universal Windows Platform Windows Runtime Vexi Ordered from more common types to less common types: Commodity computing platforms Wintel, that is, Intel x86 or compatible personal computer hardware with Windows operating system Macintosh, custom Apple Inc. hardware and Classic Mac OS and macOS operating systems 68k-based PowerPC-based, now migrated to x86 ARM architecture based mobile devices iPhone smartphones and iPad tablet computers devices running iOS from Apple Gumstix or Raspberry Pi full function miniature computers with Linux Newton devices running the Newton OS from Apple x86 with Unix-like systems such as Linux or BSD variants CP/M computers based on the S-100 bus, maybe the earliest microcomputer platform Video game consoles, any variety 3DO Interactive Multiplayer, licensed to manufacturers Apple Pippin, a multimedia player platform for video game console development RISC processor based machines running Unix variants SPARC architecture computers running Solaris or illumos operating systems DEC Alpha cluster running OpenVMS or Tru64 UNIX Midrange computers with their custom operating systems, such as IBM OS/400 Mainframe computers with their custom operating systems, such as IBM z/OS Supercomputer architectures Cross-platform Platform virtualization Third platform Ryan Sarver: What is a platform
North America is a continent within the Northern Hemisphere and all within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16.5% of the earth's land area and about 4.8% of its total surface. North America is the third largest continent by area, following Asia and Africa, the fourth by population after Asia and Europe. In 2013, its population was estimated at nearly 579 million people in 23 independent states, or about 7.5% of the world's population, if nearby islands are included. North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge 40,000 to 17,000 years ago; the so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago. The Classic stage spans the 6th to 13th centuries.
The Pre-Columbian era ended in 1492, the transatlantic migrations—the arrival of European settlers during the Age of Discovery and the Early Modern period. Present-day cultural and ethnic patterns reflect interactions between European colonists, indigenous peoples, African slaves and their descendants. Owing to the European colonization of the Americas, most North Americans speak English, Spanish or French, their culture reflects Western traditions; the Americas are accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass unknown by Europeans. In 1507, Waldseemüller produced a world map, in which he placed the word "America" on the continent of South America, in the middle of what is today Brazil, he explained the rationale for the name in the accompanying book Cosmographiae Introductio:... ab Americo inventore... quasi Americi terram sive Americam.
For Waldseemüller, no one should object to the naming of the land after its discoverer. He used the Latinized version of Vespucci's name, but in its feminine form "America", following the examples of "Europa", "Asia" and "Africa". Other mapmakers extended the name America to the northern continent, In 1538, Gerard Mercator used America on his map of the world for all the Western Hemisphere; some argue that because the convention is to use the surname for naming discoveries, the derivation from "Amerigo Vespucci" could be put in question. In 1874, Thomas Belt proposed a derivation from the Amerrique mountains of Central America. Marcou corresponded with Augustus Le Plongeon, who wrote: "The name AMERICA or AMERRIQUE in the Mayan language means, a country of perpetually strong wind, or the Land of the Wind, and... the can mean... a spirit that breathes, life itself." The United Nations formally recognizes "North America" as comprising three areas: Northern America, Central America, The Caribbean.
This has been formally defined by the UN Statistics Division. The term North America maintains various definitions in accordance with context. In Canadian English, North America refers to the land mass as a whole consisting of Mexico, the United States, Canada, although it is ambiguous which other countries are included, is defined by context. In the United States of America, usage of the term may refer only to Canada and the US, sometimes includes Greenland and Mexico, as well as offshore islands. In France, Portugal, Romania and the countries of Latin America, the cognates of North America designate a subcontinent of the Americas comprising Canada, the United States, Mexico, Greenland, Saint Pierre et Miquelon, Bermuda. North America has been referred to by other names. Spanish North America was referred to as Northern America, this was the first official name given to Mexico. Geographically the North American continent has many subregions; these include cultural and geographic regions. Economic regions included those formed by trade blocs, such as the North American Trade Agreement bloc and Central American Trade Agreement.
Linguistically and culturally, the continent could be divided into Latin America. Anglo-America includes most of Northern America and Caribbean islands with English-speaking populations; the southern North American continent is composed of two regions. These are the Caribbean; the north of the continent maintains recognized regions as well. In contrast to the common definition of "North America", which encompasses the whole continent, the term "North America" is sometimes used to refer only to Mexico, the United States, Greenland; the term Northern America refers to the northern-most countries and territories of North America: the United States, Bermuda, St. Pierre and Miquelon and Greenland. Although the term does not refer to a unifie
A video game is an electronic game that involves interaction with a user interface to generate visual feedback on a two- or three-dimensional video display device such as a TV screen, virtual reality headset or computer monitor. Since the 1980s, video games have become an important part of the entertainment industry, whether they are a form of art is a matter of dispute; the electronic systems used to play video games are called platforms. Video games are developed and released for one or several platforms and may not be available on others. Specialized platforms such as arcade games, which present the game in a large coin-operated chassis, were common in the 1980s in video arcades, but declined in popularity as other, more affordable platforms became available; these include dedicated devices such as video game consoles, as well as general-purpose computers like a laptop, desktop or handheld computing devices. The input device used for games, the game controller, varies across platforms. Common controllers include gamepads, mouse devices, the touchscreens of mobile devices, or a person's body, using a Kinect sensor.
Players view the game on a display device such as a television or computer monitor or sometimes on virtual reality head-mounted display goggles. There are game sound effects and voice actor lines which come from loudspeakers or headphones; some games in the 2000s include haptic, vibration-creating effects, force feedback peripherals and virtual reality headsets. In the 2010s, the commercial importance of the video game industry is increasing; the emerging Asian markets and mobile games on smartphones in particular are driving the growth of the industry. As of 2015, video games generated sales of US$74 billion annually worldwide, were the third-largest segment in the U. S. entertainment market, behind broadcast and cable TV. Early games used interactive electronic devices with various display formats; the earliest example is from 1947—a "Cathode ray tube Amusement Device" was filed for a patent on 25 January 1947, by Thomas T. Goldsmith Jr. and Estle Ray Mann, issued on 14 December 1948, as U. S.
Patent 2455992. Inspired by radar display technology, it consisted of an analog device that allowed a user to control a vector-drawn dot on the screen to simulate a missile being fired at targets, which were drawings fixed to the screen. Other early examples include: The Nimrod computer at the 1951 Festival of Britain; each game used different means of display: NIMROD used a panel of lights to play the game of Nim, OXO used a graphical display to play tic-tac-toe Tennis for Two used an oscilloscope to display a side view of a tennis court, Spacewar! used the DEC PDP-1's vector display to have two spaceships battle each other. In 1971, Computer Space, created by Nolan Bushnell and Ted Dabney, was the first commercially sold, coin-operated video game, it used a black-and-white television for its display, the computer system was made of 74 series TTL chips. The game was featured in the 1973 science fiction film Soylent Green. Computer Space was followed in 1972 by the first home console. Modeled after a late 1960s prototype console developed by Ralph H. Baer called the "Brown Box", it used a standard television.
These were followed by two versions of Atari's Pong. The commercial success of Pong led numerous other companies to develop Pong clones and their own systems, spawning the video game industry. A flood of Pong clones led to the video game crash of 1977, which came to an end with the mainstream success of Taito's 1978 shooter game Space Invaders, marking the beginning of the golden age of arcade video games and inspiring dozens of manufacturers to enter the market; the game inspired arcade machines to become prevalent in mainstream locations such as shopping malls, traditional storefronts and convenience stores. The game became the subject of numerous articles and stories on television and in newspapers and magazines, establishing video gaming as a growing mainstream hobby. Space Invaders was soon licensed for the Atari VCS, becoming the first "killer app" and quadrupling the console's sales; this helped Atari recover from their earlier losses, in turn the Atari VCS revived the home video game market during the second generation of consoles, up until the North American video game crash of 1983.
The home video game industry was revitalized shortly afterwards by the widespread success of the Nintendo Entertainment System, which marked a shift in the dominance of the video game industry from the United States to Japan during the third generation of consoles. A number of video game developers emerged in Britain in the early 1980s; the term "platform" refers to the specific combination of electronic components or computer hardware which, in conjunction with software, allows a video game to operate. The term "system" is commonly used; the distinctions below are not always clear and there may be games that bridge one or more platforms. In addition to laptop/desktop computers and mobile devices, there are other devices which have the ability to play games but are not video game machines, such as PDAs and graphing calculators. In common use a "PC game" refers to a form of media that involves a player interacting with a personal computer conne
A demon is a supernatural and malevolent being prevalent in religion, literature, fiction and folklore. The original Greek word daimon does not carry negative connotations; the Ancient Greek word δαίμων daimōn denotes a spirit or divine power, much like the Latin genius or numen. The Greek conception of a daimōn notably appears in the works of Plato, where it describes the divine inspiration of Socrates. In Ancient Near Eastern religions and in the Abrahamic traditions, including ancient and medieval Christian demonology, a demon is considered a harmful spiritual entity which may cause demonic possession, calling for an exorcism. In Western occultism and Renaissance magic, which grew out of an amalgamation of Greco-Roman magic, Jewish Aggadah and Christian demonology, a demon is believed to be a spiritual entity that may be conjured and controlled; the Ancient Greek word δαίμων daimōn denotes a spirit or divine power, much like the Latin genius or numen. Daimōn most came from the Greek verb daiesthai.
The Greek conception of a daimōn notably appears in the works of Plato, where it describes the divine inspiration of Socrates. To distinguish the classical Greek concept from its Christian interpretation, the former is anglicized as either daemon or daimon rather than demon; the original Greek word daimon does not carry the negative connotation understood by implementation of the Koine δαιμόνιον, ascribed to any cognate words sharing the root. The Greek terms do not have any connotations of malevolence. In fact, εὐδαιμονία eudaimonia, means happiness. By the early Roman Empire, cult statues were seen, by pagans and their Christian neighbors alike, as inhabited by the numinous presence of the gods: "Like pagans, Christians still sensed and saw the gods and their power, as something, they had to assume, lay behind it, by an easy traditional shift of opinion they turned these pagan daimones into malevolent'demons', the troupe of Satan..... Far into the Byzantine period Christians eyed their cities' old pagan statuary as a seat of the demons' presence.
It was no longer beautiful, it was infested." The term had first acquired its negative connotations in the Septuagint translation of the Hebrew Bible into Greek, which drew on the mythology of ancient Semitic religions. This was inherited by the Koine text of the New Testament; the Western medieval and neo-medieval conception of a demon derives seamlessly from the ambient popular culture of Late Antiquity. The Hellenistic "daemon" came to include many Semitic and Near Eastern gods as evaluated by Christianity; the supposed existence of demons remains an important concept in many modern religions and occultist traditions. Demons are still feared due to their alleged power to possess living creatures. In the contemporary Western occultist tradition, a demon is a useful metaphor for certain inner psychological processes, though some may regard it as an objectively real phenomenon; some scholars believe that large portions of the demonology of Judaism, a key influence on Christianity and Islam, originated from a form of Zoroastrianism, were transferred to Judaism during the Persian era.
Both deities and demons can act as intermediaries to deliver messages to humans. Thus they share some resemblance to the Greek daimonion; the exact definition of "demon" in Egyptology posed a major problem for modern scholarship, since the borders between a deity and a demon are sometimes blurred and the ancient Egyptian language lacks a term for the modern English "demon". However, magical writings indicate that ancient Egyptians acknowledged the existence of malevolent demons by highlighting the demon names with red ink. Demons in this culture appeared to be subordinative and related to a specific deity, yet they may have acted independent from the divine will; the existence of demons can be related beyond the created world. But this negative connotation cannot be denied in light of the magical texts; the role of demons in relation to the human world remains ambivalent and depends on context. Ancient Egyptian demons can be divided into two classes: "guardians" and "wanderers." "Guardians" are tied to a specific place.
Demons protecting the underworld may prevent human souls from entering paradise. Only by knowing right charms is the deceased able to enter the Halls of Osiris. Here, the aggressive nature of the guardian demons is motivated by the need to protect their abodes and not by their evil essence. Accordingly, demons guarded the gates to the netherworld. During the Ptolemaic and Roman period, the guardians shifted towards the role of Genius loci and they were the focus of local and private cults; the "wanderers" are associated with possession, mental illness and plagues. Many of them serve as executioners for the major deities, such as Ra or Osiris, when ordered to punish humans on earth or in the netherworld. Wanderers can be agents of chaos, arising from the world beyond creation to bring about misfortune and suffering without any divine instructions, led only by evil motivations; the influences of the wanderers can be warded off and kept at the borders on the human world by the use of magic, but they can never be destroyed.
A sub-category of "wanderers" are nightmare demons, which were believed to ca
Tyrannosaurus is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex called T. rex or colloquially T-Rex, is one of the most well-represented of the large theropods. Tyrannosaurus lived throughout what is now western North America, on what was an island continent known as Laramidia. Tyrannosaurus had a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 68 to 66 million years ago, it was the last known member of the tyrannosaurids, among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event. Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hindlimbs, Tyrannosaurus forelimbs were short but unusually powerful for their size and had two clawed digits; the most complete specimen measures up to 12.3 m in length though T. rex could grow to lengths of over 12.3 m, up to 3.66 meters tall at the hips, according to most modern estimates 8.4 metric tons to 14 metric tons in weight.
Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it is still among the largest known land predators and is estimated to have exerted the strongest bite force among all terrestrial animals. By far the largest carnivore in its environment, Tyrannosaurus rex was most an apex predator, preying upon hadrosaurs, armored herbivores like ceratopsians and ankylosaurs, sauropods; some experts have suggested the dinosaur was a scavenger. The question of whether Tyrannosaurus was an apex predator or a pure scavenger was among the longest debates in paleontology. Most paleontologists today accept that Tyrannosaurus was both a scavenger. More than 50 specimens of Tyrannosaurus rex have been identified, some of which are nearly complete skeletons. Soft tissue and proteins have been reported in at least one of these specimens; the abundance of fossil material has allowed significant research into many aspects of its biology, including its life history and biomechanics. The feeding habits and potential speed of Tyrannosaurus rex are a few subjects of debate.
Its taxonomy is controversial, as some scientists consider Tarbosaurus bataar from Asia to be a second Tyrannosaurus species while others maintain Tarbosaurus is a separate genus. Several other genera of North American tyrannosaurids have been synonymized with Tyrannosaurus; as the archetypal theropod, Tyrannosaurus is one of the best-known dinosaurs since the 20th century, has been featured in film, postal stamps, many other media. Tyrannosaurus rex was one of the largest land carnivores of all time. One of the largest and the most complete specimen, nicknamed Sue, is located at the Field Museum of Natural History. Sue measured 12.8 meters long, was 3.66 meters tall at the hips, according to the most recent studies, using a variety of techniques, estimated to have weighed between 8.4 metric tons to 14 metric tons. A specimen nicknamed Scotty, located at the Royal Saskatchewan Museum, is reported to measure 13 m in length. Using a mass estimation technique that extrapolates from the circumference of the femur, Scotty was estimated as the largest known specimen at 8.8 metric tons in weight.
Not every adult Tyrannosaurus specimen recovered. Average adult mass estimates have varied over the years, from as low as 4.5 metric tons, to more than 7.2 metric tons, with most modern estimates ranging between 5.4 metric tons and 8.0 metric tons. The neck of Tyrannosaurus rex formed a natural S-shaped curve like that of other theropods, but was short and muscular to support the massive head; the forelimbs had only two clawed fingers, along with an additional small metacarpal representing the remnant of a third digit. In contrast the hind limbs were among the longest in proportion to body size of any theropod; the tail was heavy and long, sometimes containing over forty vertebrae, in order to balance the massive head and torso and to provide space for massive locomotor muscles. To compensate for the immense bulk of the animal, many bones throughout the skeleton were hollowed, reducing its weight without significant loss of strength; the largest known Tyrannosaurus rex skull measures up to 1.52 meters in length.
Large fenestrae in the skull reduced weight, as in all carnivorous theropods. In other respects Tyrannosaurus's skull was different from those of large non-tyrannosaurid theropods, it was wide at the rear but had a narrow snout, allowing unusually good binocular vision. The skull bones were massive and the nasals and some other bones were fused, preventing movement between them; these and other skull-strengthening features are part of the tyrannosaurid trend towards an powerful bite, which surpassed that of all non-tyrannosaurids. The tip of the upper jaw was U-shaped, which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it increased the stresses on the front teeth; the teeth of Tyrannosaurus rex displayed marked heterodonty. The premaxillary teeth at the front of the upper jaw were packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform and c
Hangman is a paper and pencil guessing game for two or more players. One player thinks of a word, phrase or sentence and the other tries to guess it by suggesting letters or numbers, within a certain number of guesses; the word to guess is represented by a row of dashes. In most variants, proper nouns, such as names and brands, are not allowed. Slang words, sometimes referred to as informal or shortened words, are not allowed. If the guessing player suggests a letter which occurs in the word, the other player writes it in all its correct positions. If the suggested letter does not occur in the word, the other player draws one element of a hanged man stick figure as a tally mark; the player guessing the word may, at any time, attempt to guess the whole word. If the word is correct, the game is over and the guesser wins. Otherwise, the other player may choose to penalize the guesser by adding an element to the diagram. On the other hand, if the other player makes enough incorrect guesses to allow his opponent to complete the diagram, the game is over, this time with the guesser losing.
However, the guesser can win by guessing all the letters or numbers that appears in the word, thereby completing the word, before the diagram is completed. As the name of the game suggests, the diagram is designed to look like a hanging man. Although debates have arisen about the questionable taste of this picture, it is still in use today. A common alternative for teachers is to draw an apple tree with ten apples, erasing or crossing out the apples as the guesses are used up; the exact nature of the diagram differs. Some players begin with no diagram at all, drawing the individual elements of the gallows as part of the game giving the guessing players more chances; the amount of detail on the man can vary, affecting the number of chances. Some players include a face on the head, either all at once or one feature at a time; some modifications to game play to increase the difficulty level are sometimes implemented, such as limiting guesses on high-frequency consonants and vowels. Another alternative is to give the definition of the word.
The fact that the twelve most occurring letters in the English language are e-t-a-o-i-n-s-h-r-d-l-u, along with other letter-frequency lists, are used by the guessing player to increase the odds when it is their turn to guess. On the other hand, the same lists can be used by the puzzle setter to stump their opponent by choosing a word that deliberately avoids common letters or one that contains rare letters. Another common strategy is to guess vowels first, as English only has five vowels and every word has at least one. According to a 2010 study conducted by Jon McLoone for Wolfram Research, the most difficult words to guess include jazz, hajj, fizz and variations of these; the game show Wheel of Fortune is based on Hangman but with the addition of multiple-word puzzles, a roulette-styled wheel, cash awards. Brazil had a show in the 1960s and again from 2012–2013 called Let’s Play Hangman, hosted by the legendary Silvio Santos. Brazil would get its own version of Wheel of Fortune, running from 1980 to 1993, again from 2003 to 2012, again since 2013 to the present.
These shows were hosted by Santos. In July 2017, the BBC introduced a game show of its own called Letterbox, based on Hangman; the following example game illustrates a player trying to guess the word hangman using a strategy based on letter frequency. As the player continues, a part of the stick figure on the noose is added. Once a full body is drawn, the game is over, the player lost
A skateboarding trick, or a trick, is a maneuver performed on a skateboard while skateboarding. Skateboarding tricks may vary in difficulty. Though skateboards emerged in the 1900s, skateboarding tricks like the ones done today did not appear until decades later. In the 1970s and earlier, the most common tricks were "2D" freestyle types such as manuals and pivots. Only in the 1980s and early 1990s were common modern-day tricks like the ollie and kickflip invented by Alan Gelfand and Rodney Mullen, setting the stage for other aerial tricks. An Ollie is a jump; this motion is attained with a snap of the tail and sliding your front-foot forward to reach any altitude. A lot of technical tricks transpire from this element. A nollie is when the back wheels leave the ground first by snapping the nose of the board, with the back foot sliding towards the tail. A Grab involves floating in the air, while using either hand to hold the board against the feet or keeping constant and careful pressure on the board with the feet to keep it from floating away.
Indy Grab combine rotation with different grabs. This class of tricks was first popularized when Tony Hawk became famous for his frontside airs in empty swimming pools in the late 1970s and has expanded to include the bulk of skateboarding tricks to this day, including the ollie and all of its variations; the 900 and 1080 fall under the class of aerials, though these are confused with aerial grabs. Flip tricks are a subset of aerials. An example is the kickflip, the most known and performed flip trick; the board can be spun around many different axes as part of a flip trick, thus combining several rotations into one trick. These tricks are undoubtedly most popular among street skateboarding purists, although skaters with other styles perform them as well. Combining spins and flips is popular in today's culture. A common trick in skateboarding lines is a 360 flip, or tre flip. A 360 flip is the combination of a skateboard spinning a kickflip. There are double kickflips and triple kickflips which are difficult but regarded in the skateboarding culture.
Freestyle skateboarding tricks are tricks associated with freestyle skateboarding. Slides and grinds involve getting the board up on some type of ledge, rail, or coping and sliding or grinding along the board or trucks, respectively; when it is the board, contacting the edge, it's called a slide. Grinding and sliding skateboards started with sliding the board on parking blocks and curbs extended to using the coping on swimming pools stairway handrails, has now been expanded to include every possible type of edge. Grinds and slides on street environments were brought to mainstream skateboarding by professional skateboarder Natas Kaupas