Foursquare

Foursquare is a local search and discovery service mobile app which provides search results for its users. By taking into account the places a user goes, the things they have told the app that they like, and the other users whose advice they trust, Foursquare provides recommendations of the places to go around a user's current location.

The service was created in late 2008 and launched in 2009 by Dennis Crowley and Naveen Selvadurai. Crowley had previously founded the similar project Dodgeball as his graduate thesis project in the Interactive Telecommunications Program (ITP) at New York University. Google bought Dodgeball in 2005 and shut it down in 2009, replacing it with Google Latitude. Dodgeball user interactions were based on SMS technology, rather than an application. Foursquare was the second iteration of that same idea, that people can use mobile devices to interact with their environment. Foursquare was Dodgeball reimagined to take advantage of the new smartphones, like the iPhone, which had built in GPS to better detect a user's location.

Four square

Four square, also known as downball, squareball, blockball, boxball, champ or king's square, is a ball game played among four players on a square court divided into quadrants. It is a popular game at elementary schools with little required equipment, almost no setup, and short rounds of play that can be ended at any time.

Four square is usually played with a rubber playground ball, on a square court with four maximum players. The objectives of four square are to eliminate other players to achieve the highest rank.

Playing environment

Four square is played on any hard-surfaced court, such as wood, concrete or asphalt. There is no official court size, but typically courts measure between 10 to 20 feet on a side, and divided into four smaller equal-size squares. Each of the four squares has a rank and is occupied by a single player. The ranks may be arranged so that either the highest ranking square is positioned facing the lowest ranking square, or the ranks increase as one moves clockwise (or counterclockwise).