John Zorn's improvisational game meets musical composition, Cobra is based on a loosely structured set of rules controlled by Zorn as 'prompter'. Working with a set of cues [as notations] on cards, and sets of basic rules corresponding to those cues, Zorn sets off an indeterminate play of instrumentation and improvisation. The basic form of the Cobra games works as follows:
Players raise hands to get the prompter's attention.
The prompter selects a player.
The selected player indicates the desired card by pointing to a body part that indicates the type of cue, and holds up the number of fingers indicating the specific cue to be given.
The prompter then shows the corresponding cue card to the ensemble---thus putting it into 'play'.
The ensemble performs according to the rule that is represented by the cue card.
This is repeated from until an ending cue is given.