Three guys walk into a bar - a physicist, a painter and a philosopher with a weak bladder. Then three more guys walk into a bar - an agent, an inventor, and a far-out customer who seems otherworldly. Aha! A setup for a double punch line.

But Steve Martin's first full-length comedy,

Picasso at the Lapin Agile,

which debuted in 1993 and is in a rousing production at the Delaware Theatre Company in Wilmington, is more than two good yuks in a single joke. It's full of 'em, a one-act about Albert Einstein and Pablo Picasso meeting, just before each became famous, at a Paris bar. (The Lapin Agile still operates as a cabaret in the Montmartre district; Einstein's introduction to Picasso there still operates only in Steve Martin's mind.)

What ensues is high-level loopiness, Martin-style: banter about whether the theory of relativity can be funny, or about when something is post- or neo-romantic, or whether a painting of sheep is really not a painting of sheep at all, or a painting. It's cerebral fun - and very funny, tangents boomeranging here and there from the 20th century's infancy, with everyone in the bar musing on the future.

This endearing play is decidedly down-to-earth, even referring to itself as a piece of theater on several occasions. Einstein (Matt Pfeiffer, in his first role since winning the Barrymore Award's $10,000 emerging artist prize this fall) and Picasso (Caesar Samayoa) have their talents, for sure. But they also display everyday concerns ("I discovered at an early age I'm the kind of person who will always look 86," Einstein shrugs), and get into bar tiffs.

"Maybe you're a fake!" Picasso challenges, even though Einstein can tabulate the bar owner's knotty inventory bill instantly in his head.

"Maybe you're an idiot-savant ... and hold the savant!" Einstein shoots back.

The men are egged on, challenged and calmed by a host of others - many played by actors who, like Pfeiffer, are regular presences on some of the region's best stages: the bar owner (Jeb Kreager), his mistress (Lee Ann Etzold), a weak-bladdered philosopher who is the play's 19th-century voice (John Morrison), Picasso's agent (Aaron Cromie), one of Picasso's umpteen girlfriends (Karen Peakes), an inventor with all the wrong mental moves (Nathan Holt), and a visitor from a cultural future no one could have comprehended back in 1904 Paris (Danny Bernardy).

The show is directed with an ear for the barrage of funny references to their lives then, and ours now, by David Stradley (he directed the company's

Art

last season), and is cleverly lit by Troy A. Martin-O'Shia and designed by Eric Schaeffer to unfold within three huge frames that could be for paintings or as wall supports of, say, a cafe. In a play basically about the beauty in any act of meaningful creation, the cast and the creative team practice what Martin ultimately preaches.

Picasso at the Lapin Agile

Through Dec. 21 at the Delaware Theatre Company, 200 Water St., Wilmington. Tickets: $36-$49. Information: 302-594-1100 or

» READ MORE: www.delawaretheatre.org

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Contact staff writer Howard Shapiro at 215-854-5727 or hshapiro@phillynews.com.