In the Command Center, the side screens displayed a hundred bubbling trails crisscrossing in wild patterns as the pirates released anti-anti-torpedoes to counter the city’s defense. Made of ceramics and powered by compressed air, the deadhead projectiles were invisible to magnetic sensors, so The Cube master-computer formed vector graphics of the incoming projectiles based on sonar readings; glowing green lines to show the silhouette of an enemy incoming where the passive sensors indicated they should be located. The accuracy of the plotting and graphics was highly doubtful.