In 1968, filmmaker William Greaves assembled a small crew in Central Park for an experiment in freewheeling deconstruction – or, as one participant called it, a “feature length we-don’tknow.” The working title was “Over the Cliff” – the cliff, in this case, being every normal procedure of moviemaking. What ultimately came together in the editing room is known as “Symbiopsychotaxiplasm: Take 1,” a minor avant-garde classic opening today at the IFC Center in a new 35mm print.

The rehearsing of a “purposefully unsatisfactory screen-test” provided the pretext for an effervescent exercise in postmodernism. Don Fellows and Patricia Ree Gilbert play Alice and Freddie, a married couple having a bitter public argument. The dialogue, semi-improvised, is fully self-reflexive – and rather silly. “Come on Alice, stop acting,” retorts Freddie on accusation of “faggotry.” “You’re projecting, Alice.”

Of course she is. Who isn’t when the camera’s turned on? The crew is disconcerted to discover the director assuming the persona of “director.” While one cameraman films the actors, another is filming the filming. Mr. Greaves then cut and shuffled this footage into diptychs and triptychs, playing images in counterpoint, bifurcating lines of attention, multiplying digressiveness.

Anything and everything that comes within the vortex of the camera lens was allowed in the final “Take”: shot setups and actors’ conferences; policemen on horseback demanding to see permits; lovers caught unawares; dog walkers; local kids crowding the scene.

No one involved, including Mr. Greaves, knew exactly what they were attempting to capture. “Is the genius of the film that it reveals something or nothing?” The question is posed during one of several private crew conferences captured in the movie. Unbeknownst (presumably) to Mr. Greaves, his collaborators hijacked the production and turned the cameras on themselves, recording their attempts to decode the rules of the game.

What’s in the director’s mind? What’s the function of the crew and the actors? Is the goal simply to “function in terms of the reality of the moment”? The spirit of debate, as of the movie itself, is inquisitive, cheerful, generous. Yes, there is symbiosis, psychology, taxonomies, and much else circulating in the intellectual protoplasm of the movie, but don’t let the title put you off. “Symbiopsychotaxiplasm: Take 1″is flower-power Pirandello, a High 60s groove on, like, “supra levels of reality,” man. Or as another crewmember ponders, “Sure, it’s a movie, but who’s moving who?”

A climax, of sorts, arrives one afternoon when Mr. Greaves sits everyone down for a bit of straight talk. He defines his role, heretofore inscrutable, as an extension of “the establishment,” positing an unsatisfactory situation the actors are encouraged to alter or overthrow. Perhaps that’s just another tease, twist of the labyrinth, or simple canard. It does not, in any event, explain the next sequence of the film, in which another pair of actors play the shtick as musical.

The final scene is given over to a drunken French painter, homeless and garrulous, who wanders into the production and promptly commandeers it for an improvisatory tour de force. They don’t make ’em like that anymore, nor like “Symbiopsychotaxiplasm: Take 1,” a blast from the past that’s as fresh as tomorrow.

Until November 1 (333 Sixth Avenue at West 3rd Street, 212-924-7771).