Lists for thread safe data exchange between main and draw thread. Latest snapshot of the potential field to be displayed. This is a certain pontetial field of a certain pedestrian. See 'Simulation' for more information. For debug purposes. Updated by popDrawData(). Latest snapshot of the jts diagram to be displayed. Updated by popDrawData(). Synchronizer object used to control access to the simulation data exchange structures to avoid threading issues. The observation area to display. Updated by popDrawData() with the latest observation area snapshot.