Experiencing A PARALELLOGRAM at Second Stage is the theatergoer’s version of walking into a meadow, spotting a butterfly, trying to catch it — and always missing it at the last second.

You may find that every time you say “Ah! This is what this play is about!” it takes a turn that may make you say “Now what’s going on?” It’s ostensibly about life, the choices we make, the mistakes we make, the 20-20 hindsight that older people have and the myopia of the young.

(Or is it?)

There’s talk of deaths 25 years hence in Guatemala, Australia and Fort Lauderdale. Mentions of dinosaurs and dead birds seem to be shaggy dog stories. Then there are matters of ethics: should one fish in an area where a professional fisherman has just died and his body hasn’t yet been retrieved? “It’s important not to jump to any conclusions,” one character says around the time many theatergoers would prefer to jump ship.

Coughs from the audience usually start in Act Two of a frustrating play; here they came early in Act One. When the famous line came out of “moments of your life you’re never going to get back,” there was a stony silence of recognition. The biggest laugh came from an offhand mention of Trip Advisor.

Worse, as the play continues on its two-and-a-quarter-hour journey, there’s some collateral damage that makes a confusing experience into an ultimately unpleasant one.

A PARALLELOGRAM starts with Jay emerging from another room and asking his girlfriend Bee “Why am I always the bad guy?” He goes into a defense of his recent behavior, but he makes no discernible impression on her.

Bee busies herself by playing solitaire.

To be fair, someone else is commanding her attention: Bee 2, as she’s called: Bee’s septuagenarian self who’s also busy dealing out seven piles of cards. Because Bee 2 has been-there-done-that, she’s able to give the thirty-five year-old Bee previews of coming attractions.

Considering where Bee is right now in her life – a regional manager for Rite-Aid involved with Jay, a divorced husband and father with whom she has issues – we’re not surprised that Bee 2 doesn’t use the words “lollipops” and “roses” in her predictions.

Because we get two Bees from the outset, we assume this is the character with whom we’re supposed to like and bond. Playwright Bruce Norris – winner of a Pulitzer and a Tony for CLYBOURNE PARK — will ultimately suggest that Bee’s biggest opponent is herself and not simply in solitaire.

Before that, though, Jay is on the phone with his son whom he doesn’t call by name, but prefers to address as “Goofball.” This further alienates us from him.

So we’re a little amused when Bee confuses Jay by ostensibly speaking and listening to thin air. But as this happens time and time again, we’re not as charmed. Jay makes many, many sincere attempts to understand Bee. He does better than many would in multiple exceedingly frustrating situations. So A PARALLELOGRAM ultimately turns from this funny if inscrutable play into one where we feel for him more than we do for Bee.

No need to blame director Michael Greif or the cast. Celia Keenan-Bolger is one of our best actresses at making exasperation seem cute. At one point she stands on the bed and moves back and forth as if she’s in a boxing ring ready to tackle her opponent. She’s had a lot to tackle in this play, and she isn’t defeated by the material.

As Jay, Stephen Kunkel has the patience of four saints in both acts. Juan Castano, playing a handyman whom Jay worries is getting too handy with Bee, must play low-key for most of the show, which he does well; he’s even better when it’s his turn to take command.

Last but hardly least is Anita Gillette who gives an astonishing, multi-award-deserving performance. Bee 2, as the Voice of Experience, has all the answers, but she dispenses them so matter-of-factly that Bee must play catch-up all the way. Gillette still has that droll delivery that she can adeptly mix with devilish panache. What fun she and Keenan-Bolger give us in their verbal ping-pong matches.

Not only is she the sardonic, seen-it-all Bee 2, but she’s also Bee 3 — a doctor who sports an unctuous let’s-pretend-nothing’s-as-bad-as-it-seems smile. And yet, her caring and wanting-to-help demeanor shines through and shows us a real human being who remembers that she took the Hippocratic oath. You can only hope that when you’re hospitalized, you have such an on-the-ball physician.

Best of all, Gillette isn’t remotely through. There’s a Bee 3 as well – a Spanish abuela who turns up to have a few more comments. Gillette may well have more lines than anyone else on stage and makes us always glad to hear from her. In A PARALLELOGRAM, she’s on the square.