having decided to sneak out early, manfred casually stood up and surveyed the cube horizon for those that might spot him
"in a vast cubicle office environment, when one stands up in one's own cube and looks along the tops of the many cube walls stretching out to the horizon
"having decided to sneak out early, manfred casually stood up and surveyed the cube horizon for those that might spot him" What is the definition of "cube horizon"?