Spack Fur Patterns

The Spack as a whole are something that did not really turn out as useful as I thought they would. Cats do make excellent spies, but on the whole the species adapted to their new traits a lot more than intended.
What I meant to turn into a way to surreptitiously gather information about areas and then relay that information back in a seemingly innocuous way, has now turned into a primary means of communication for the spacks.
The alterations of their fur patterns were meant to be almost involuntary, dealing with the details of the room they entered, the conversation held, etc. Instead, it's become more controlled, which interestingly means that instead of dealing in body language and smells and the occasional meow, they communicate using those patterns, and as such have started developing some rather interesting levels of intelligence.
The language is a sequence of color changes on the fur of the animal, using a binary system of switching between a primary color and a secondary color. For calicoes, this sometimes means a primary color and multiple secondaries, and it's dependent on the translator to figure out which is which.
While I remain fairly confident that I'm the only person currently capable of reading the spy information, the spacks have developed a larger scale and less detailed (but no less nuanced) method with their fur. Particular patterns will form to indicate to those around them what is safe, who is interested in mating, where the good food is. Recently, I've even noticed some complaints about things like temperature.
At least, I think that's what it means. Dealing with something of an alien way of thinking here, and it's my best guess as to what each pattern actually refers to. Even so, it's interesting how they've started using it more and more, staring at each other's backs and tails intently.
One pattern I have been able to identify and could teach to someone else is "hungry." The fur forms a spiral pattern that ends with a primary color dot at the position of the spack's stomach.