»Thinking Machine 4«, 2004 explores the invisible, elusive nature of thought. It is an artificial intelligence program, ready to play chess with the viewer. If the viewer confronts the program, the computer’s thought process is sketched on screen as it plays. A map is created from the traces of literally thousands of possible futures as the program tries to decide its best move. Those traces become a key to the invisible lines of force in the game as well as a window into the spirit of a thinking machine. By Martin Wattenberg and Marek Walczak.