Each magnetic card, like its owner, is unique. ¢apital magneti¢, by Mark Trayle, is a network-based installation that explores the musical possibilities of the credit card. Participants can use their credit cards and bank cards to compose pieces of music in cooperation (or competition) with other participants. Special ATM machines are used to read the card: they contain a PC, a monitor, a credit-card reader and two speakers.
Each time a card is swiped the contents of its magnetic stripe are captured and parsed to form the melodic motifs of a short musical composition. Using genetic algorithms, compositions compete in a simulated music marketplace. Some become dominant, others less 'popular'. Some combine to form new 'styles' or 'genres' that in turn influence the more popular ones, etc.