Although only having had a 13 episode order, the producers had begun planning a 14th episode in case CBS decided to pick it up. CBS cancelled the series after 10 episodes and the 14th, called "Head Trip", never made it past paper.
The symbol used is an Escape-Time fractal, a version of the Julia Set, a recursively constructed shape related to the more famous Mandelbrot Set.
The series had a three-year planned arc which would have been reflected in the series title changing to "Foothold" in season 2 and "Stranglehold" in season 3, to reflect terms for the stages of the invasion in Dr. Caffrey's contingency plan.