Football on TV: A pass to the left, a gap in the defence, an open striker at the edge of the penalty area. Suddenly, the picture freezes. Lines and diagrams appear between the players. An arrow indicates the trajectory of a safe pass to the open striker, others highlight possible goal-scoring trajectories. Such graphic analyses have become indispensable for professional football broadcasters. They help viewers understand the dynamics and tactics of the match as well as the decisions made by the players.