I have a hard time passing up anything billed as a once-in-a-lifetime experience, so I was keen to see the revival of this seminal work from 1979. The hour-long program consists of three sequences, each approximately 20 minutes long, which have eight dancers (four men, four women) bookending a solo piece originally performed by Childs (now close to 70), now danced by Anne Lewis. The music for all three sequences was composed by Phillip Glass and the performance is accompanied by a film by Sol LeWitt featuring the work's original dancers performing the work which plays almost continuously on a scrim at the front of the stage.

In 1979 this meant the dancers were performing alongside, underneath, or next to images of themselves on a screen. In 2011, there are new dancers performing simultaneously with a film of the their counterparts from 1979. The result is mesmerizing and one thing is obvious- today's dancers are much better.

Childs' choreography, like Glass' score, is based on the repetition of distinct elements which create a cumulative effect as they unfurl over time.In the first sequence the dancers do little more than skip and twirl across the stage, entering from stage left, returning from stage right, slightly dipping their shoulders before they disappear from view, hinting that there is something slightly out of balance about this world but it just keeps moving on regardless. The dancers start to move faster as the piece moves from a 12 count to 24, and then to 48, eventually creating a flurry of bouncing bodies across the stage, all performing the same moves while moving in opposite directions, resulting in an effect that can only be described as a visual euphoria.

Coming to an abrupt ending (it is Glass, after all), the second sequence begins with an extended stationary pose by Childs on the scrim. If you didn't notice her blink a few times one may have thought it a still photograph. After a couple of minutes the film disappears leaving Lewis onstage by herself, where she performs a solo that resembles much of what took place during the first sequence but is actually quite different. Alone onstage, with the film of Childs returning from time to time, Lewis skipped and danced to the music but at the end of almost every pattern she turned and threw up her hands, then turned right and repeated the gesture. To me it seemed like a lone dancer, a woman, aimlessly throwing up her hands to fate as if to ask "What the hell am I dong here?" And the question is never answered, though it is repeated countless times. After 20 some odd minutes, it began to grate. What was fleet in the first sequence seemed plodding in the second. There's probably something to unpack there, but you'll have to ask me about that in a couple of days.

The third sequence featured the eight dancers from the first, performing similar steps but now they seemed unbound and even more exuberant. At many points in this segment dancers would move to the corners of the stage and stop, only to pirouette back into the music and the floor on a cue that must demand enormous concentration to keep track of. The net result was a joyous display of the sheer pleasure of mobility and form and watching it was exhilarating as the cast of 1979 performed the same moves on the scrim. It's a potent and heady experience.

The cast of dancers was excellent, and though the program doesn't list them along with photos, my favorites were the bald male and the shorter of the two blonde females. Onstage were Katie Dorn, Sharon Milanese, Katherine Fisher, Shakirah Stewart, Anne Lewis, Ty Boomershine, Patrick O'Neill, Travis Magee, Vincent McCloskey and Joshua Green, all of whom did a fabulous job.

My companion, an admitted non-fan of Glass' music, thought it entirely appropriate and enjoyed it. If the second movement were more involving I would say this would be an early contender for best of 2011. The outer movements are superb, so check out the last performance tomorrow night. There is also a solo performance by Glass tomorrow at 3:00 featuring music from and based on this score. Highly recommended, presented by YBCA and San Francisco Performances.

I should mention that beforehand we had another excellent meal complete with great service at Credo- I love this restaurant. Do check it out and I'm curious about the moustache party- if one of you reads this fill me in on what that was all about. I've never seen moustachioed women look so hot. Speaking of hot, the girl at the corner of Cyril Magnun and Eddy at 10:00 pm in the red dress and those black boots- those boots were the bomb.Damn. Even Penelope thought so, and she's a tough critic.