We have made a robot soccer model using LEGO Mindstorms robots, which was shown at RoboCup98 during the World Cup in soccer in France 1998. We developed the distributed behaviour-based. approach in order to make a robust and high performing robot soccer demonstration. Indeed, our robots scored in an average of 75–80% of the periods in the games. For the robot soccer model, we constructed a stadium out of LEGO pieces, including stadium light, rolling commercials, moving cameras projecting images to big screens, scoreboard and approximately 1500 small LEGO spectators who made the “Mexican wave” as known from soccer stadiums. These devices were controlled using the LEGO Dacta Control Lab system and the LEGO CodePilot system that allow programming motor reactions which can be based on sensor inputs. The wave of the LEGO spectators was made using the principle of emergent behaviour. There was no central control of the wave, but it emerges from the interaction between small units of spectators with a local feedback control.