LYNN – It’s just after 3:30 on a Wednesday afternoon, and Joe Picano is doing his best “marching robot” impression, his elbow and knee joints comically locked as he parades in front of his musicians.”This is marching, but this isn’t a marching band. What kind of band is it?” asks Picano, who’s also the public schools’ fine arts director.”A jazz band” a few of them murmur tentatively, if not annoyed at the obvious question.”That’s right, a jazz band,” he says, with the emphasis clearly on “jazz.” “So you’re going to have a different style and approach to the music.”Welcome to Breed Middle School auditorium, where the all-city middle school jazz band is rehearsing the 1958 Moe Koffman tune, “Swingin’ Shepherd Blues.” As of this rehearsal, in early April, it may or may not be included in a concert to be given in May.Picano tells the group that this piece, frankly, is geared to musicians that are above a middle school jazz band’s skill level and more suited to a high school jazz band. He wonders aloud if they can get it in shape in time. It’s going to take work, he tells them. The trumpets have solos that they’re going to work on with their teachers privately. The percussion is going to have to learn how to set the pace, or else the other instrumental parts will be crashing into one another and the whole piece could fall apart.It’s one month later, and the jazz band is back in the auditorium and still rehearsing “Swinging Shepherd Blues.” Picano is still wondering whether to include the piece in the program for May 22.Picano’s approach is fun, but firm. A couple of the trombone players are kibitzing as Picano ties to explain a rhythm.”It would be rude of me to interrupt while you’re talking,” he says, “so perhaps I should wait until you’re done.”The young musicians get the point and zip it.Like the piece they are rehearsing, which has sections that consist of a musical conversation among the trumpets and the saxophones, the trombones and the flutes and, this year, a violinist and cellist, the rehearsal is a conversation between conductor and musicians.Or a coach and his athletes.Sometimes the advice is direct and forceful: “If you can’t do this, I’m going to have to toss this in the wastebasket,” Picano warns.The robotic Picano of a month earlier returns in an attempt to demonstrate that the band’s playing remains stilted.”What’s a swing? What does it do?” Picano asks the group. He’s not talking about the music now. He’s talking about the common piece of playground equipment.His right arm waves gently back and forth, back and forth. “That’s a swing. And that’s swing. It’s smooth.” He talks some more about being “in the groove.”Sometimes his advice turns poetic.”Picture yourself tracing your name in a bowl of whipped cream, writing your name with your fingers,” he says. “That’s smooth.”He raises his hands to get the band ready to play. He has to stop the group several times in mid-song to correct a melody here, a rhythm there. And then comes the ultimatum.”Are we going to be able to do this?” he asks.”Ratta-ta-ratta-ta-tat,” goes the snare as the first measures kick in. It’s apparent during this take that the band is figuratively tracing their fingers in that bowl of whipped cream, clearly relaxed and having fun.From the smile on his face, Joe Picano finally likes what he’s hearing. After the final chord there’s that moment of silent anticipation.”It’s in!” he exclaims, to the relief and joy of the players.You can hear “Swinging Shepherd Blues” Wednesday night at 6 p.m. at Breed Middle School.Victor DeRubeis can be reached at [email protected].