Each card is a member of a four-card set. If all four cards are solved by a player, they receive double points for each card in the set. As of February 2020, two cards from the first season are yet to be solved:  Two cards are no longer in circulation. The cards were excluded from wave-three print runs because they did not fit on the print layout. While these problems have been rectified, Mind Candy has no plans to replace or reprint these cards in the future. They are:  The puzzle cards are intended as an introduction to the characters and story of Perplex City itself, and the deeper mysteries of the Cube theft. Clues found on the cards direct players to various websites, blogs, emails, phone calls, and SMS messages, originating from Perplex City. These often feature puzzles of their own, whose solutions lead to further puzzles. Frequently these puzzles require players to co-operate in reaching various goals. Perplex City has been running since late 2004, much longer than the traditional ARG. Its longevity has allowed for a number of events that simply would not be possible within a two-month traditional lifespan of an ARG. Some examples of this include:   In late 2006, Mind Candy released Perplex City: The Board Game. Players solve anagrams, logic problems, visual puzzles, and trivia questions to collect a set of colored stones. Players can also challenge one another for their collected stones. To win, the last stone must be collected through challenging another player. The rules insert maintains an in-universe approach to Perplex City, giving background about its puzzle-loving citizens and a fictional history of the board game. The Mind Candy cards were first released in select outlets arounds the world, but are increasingly readily available from retailers both on- and offline. On September 7, 2006, Mind Candy announced that GameStop was to begin carrying Perplex City cards in 700 stores in the United States. As of September 26, 2006, some 682,425 cards have been marked as solved on the Perplex City leaderboard, with 45,215 players registered. Mind Candy received a round of venture capital worth $3 million from Index Ventures, an investor in Skype and other technology companies. In June 2007 Mind Candy announced that it would be putting season 2 of its ARG on hold indefinitely. Mind Candy's focus later moved to the Moshi Monsters franchise and the Perplex City project was abandoned. The reviewer from the online second volume of "Pyramid" stated that "The object of the game is, well . . . that depends.