A plot of the arena, objects, and zones.

<p>The large circumference represents the 6 x 5.6 m arena, and the 16 dark squares (■) represent the 16 equispaced objects. Dashed lines represent the virtual division of the arena as used by the tracking system. The dashed square around each object represents the object zone, and the 16 object zones together comprise the grid zone. Four corner zones and four perimeter zones (each connecting two adjacent corners) were determined along the walls of the arena.