Finally, the epic refactor, whose original purpose was to break down the huge Simulation class into its multiple aspects (element representations and collections, recorder, core, timed/timeless...), has progressed so far, as to pass the unit tests. The refactor also introduces the Net::DataSet class, representing a recording of the selected feature set of the net state. For this, classes Net::State, Net::State::Feature, Net::State::Features (ie. feature set), Net::State::Features::Record were created, along with others, such as those representing the features of marking, gradient, delta, firing and flux. Making this work has been enough for today, next task at hand is to make the acceptance tests pass.