The lights fall. The stage manager enters. "If you're expecting to see a regular play, you're not going to," he says. This disclaimer issued, we the audience shift in our seats and glance at one another.

There are, after all, certain things we expect upon entering a theater: characters, setting, plot, movement of this plot from exposition to climax to denouement. We cling to our conventions, even if we do not mean to, even if we do not want to. Convention is almost all we ever see--are we to blame?

Straightlines, an original work written and directed by Patrick Tan and produced last week in the Experimental Theater, undeniably breaks convention. Tan calls it a "Performance Piece for Six Individuals." This two hour production, incorporating light, dance, video, music, and props, is really no more than a series of good visual images.

The production is divided into a prologue, four sections, three dance breaks and an epilogue. There are also three stretch breaks. Those of us in the audience who have been following our programs shift and glance again at one another. "Does he want us to stand and stretch?" we wonder.

If you ask someone what this show was about, the chances are good that the answer will be a shrug. We examine the title. References to and images of straight lines do recur throughout the show. One actor tells us it takes four straight lines to play tic-tac-toe. Another says enormous straight lines, only visible from the air, were drawn on the ground in ancient times, possibly as runways for aliens. We learn language and letters have straight lines.

"Language is the base of society. The alphabet is the base of language," one actor says. The theme of what language is and what role it plays in communication, in society, is vaguely developed in the show. At one point, one of the actors climbs a stool and spraypaints dots, not letters, onto a slideshow image of a crossword puzzle.

Breaks from convention seem to be de rigeur in this show. The first section is called "The Exploration of Conventions." The different actors read definitions from the dictionary, interviews from American Theater, and excerpts of Pynchon's Gravity's Rainbow. We are also told in the program that we get a deconstructed version of As You Like It, but we are not sure we ever do. Before we think it has started, the first section is over, and the six actors take a dance break.

The dance breaks offer some of Tan's best images. Ambiguously titled things like "The Happy End," or "Lethargy" or "Mundanity," they are well-choreographed interludes of modern dance movement. The music includes David Byrne, Brian Eno, and Philip Glass.

The dancers make good use of the whole stage, darting from one side to the other. They roll from the ground to medium platforms, to high platforms, to the balcony, in high speed and slow motion. The energy they create fills the stage and spills out into the audience. But they end as abruptly as they begin.

The six actors, who address each other on stage by their real names, hardly seem to be acting at all. They do an excellent job of comfortably keeping their positions in the piece, never over shadowing one another or the imagery. No effort is made to develop character. On the stage, they are objects, just as the lighted Christmas tree, the venetian blind, and the alarm clock are objects.

Straightlines moves from extreme to extreme, at times engaging us with excellent visual images, at times tiring us with repetiton. Tan could have edited and shaped the show to be more consistently stimulating.

The echoes of Brecht in this production are easily perceived--we are always conscious of being in a theater, always looking for the message.

The museum- or theater-goer will often look too much for meaning, for some voice of expression hidden in a play or painting's abstraction. Sometimes we think we have found it, and this encourages our search. But, more often than not, we only find disappointment.

All we can do, and maybe all Straightlines asks us to do, is begin appreciating good visual images for being good visual images, ones in which all the variables of lighting, set, music, dance and voice, work together to shape an aesthetically pleasing whole.

Some of the images Tan creates are effective portraits. In one piece, called "Positron," two twins, one wearing white, the other black, slowly dance to Philip Glass' "Metamorphosis One," and exchange clothes. Then one twin carries the other off the stage.

In the last section, called "Resolution and Emergence," we are left with this image: a Christmas tree blinking its lights behind a screen onto which enormous slides of statues are projected.

An actor, small in comparison to the projections, matches the statue's poses while a photographer snaps pictures. Three other actors sit on a platform, stage left, speaking in broken sentences about the day and the weather and the sun and the sky.

Even if we occasionally wonder if some of the scenes were created around what Tan found in the American Repertory Theater prop room, we are often startled by their power.

Watching Straightlines is similar to visiting a contemporary art gallery where the images simply come to us. But when the images fail, we are left with little else in the piece.

The show is two hours of image after image. It is certainly too long for the traditionalist, who will be frustrated by non sequitur scenes that are not held together by even a thread of continuity, much less the development of plot or characters.

But with a different set of expectations and a little patience, Straightlines is an enjoyably different and sometimes extremely creative performance. The purpose of art, is has been said, is to disturb, not reassure. Tan will not reassure us with convention. This is not a "regular play," and if the playwright leaves us shifting in our seats and glancing at one another, maybe it is we who should readjust.