Tom Sotis presents the Opposition Triangle, which consists of Tactics, Dueling, and Sparring activities explored through Ecological Dynamics and Guided Discovery Coaching. (There is a pdf on my website explaining more of those topics).

Tactics:
Attacking Tactics: Single, Combo, Fake, Grab/Disarm
Countering tactics: Jump-backs, Pass, Stop, Grab/Disarm

Dueling:
Fatal Error: any touch anywhere is fatal (zero margin of error),
Major Error: lose further use of any limb that is struck (narrow margin of error).
Minor Error: one pass for the first strike on a limb or torso (wider margin of error).

Sparring:
Configurations of lead, hand, hold, and height
Experimentation to discover solutions to problems
Recognition to develop the ability to read your opponent