source: [□] □ □
destination: [□=□] □ □
spec: The ball , covered with numbers indicating angle measurements ( a zero is added as the last digit of each ) , moves in response to software-generated commands to depict the current orbiter attitude in terms of pitch , yaw and roll . If an author does not want to deal with the event , I just make certain his / her story precedes the story that contains the event .