Abstract: The present disclosure relates generally to gaming systems, machines, and methods and, in particular, hidden symbol tracking. As an example, an electronic gaming machine is described that includes a set of reels, where each reel in the set of reels includes a plurality of symbol regions with at least one symbol provided therein, and where a first reel in the set of reels includes a hidden symbol that is capable of different presentations based upon having different lighting conditions applied thereto.