The second movement was penned by the public and played con brio, with verve. Loyal, would-be and discouraged patrons of the Kimmel flocked to forums in January to give input. They sang mostly in unison about what worked, what didn't, and how to change the place.

Next, that feedback was turned over to design students at the University of Pennsylvania and the University of the Arts. They're using it to create ideas for a revamped, livelier Commonwealth Plaza beneath the soaring glass vault.

This third movement will reach its high point April 14 as the student visions are presented for public comment at the Kimmel's Perelman Theater. You're invited. The event will run from 7 to 9:30 p.m. Space is limited, so register to attend at the Web site (www.planphilly.com/kimmel) of PennPraxis, the design consultant that has managed this process for the Kimmel.

The final movement in this civic symphony will be up to the Kimmel's leadership, to choose which ideas for enlivening the building they want to try.

The project team, of which I'm part, distilled the public's energetic input into a set of principles that the designers are using to inform their creative work.

Here are the Kimmel Center Principles. They incorporate ideas from the forums and from dozens of essays sent in response to my columns about the Kimmel. (You can see those essays, plus video of the forums on the Web site.)

1. Inside/out and Outside/in. The outside of the building must let the public see, hear and feel what is happening inside the building. The outside - now regarded as foreboding, dull and confusing - should broadcast a sense of excitement onto the street and make clearer how, where and when to enter. In sum, the exterior must more effectively explain, promote and invite.

2. Treat Commonwealth Plaza as a third, inclusive arts venue. The grand public spaces of an arts center should be filled with the sights and sounds of art. Let music permeate the space beyond performance times. Locate and use the stage in the plaza to lure members of the public who don't now consider the Kimmel their arts center. Use varied performances by diverse groups in this third venue to address the center's image problems with affordability and inclusion.

3. Create magnets to lure mixed uses and mixed users. Vibrant town squares are rich in things to do, appealing to a variety of tastes. With its location and imposing facade, the Kimmel must work hard to lure into its public spaces on a daily basis people who want to linger. Create an iconic focal point and gathering spot in the lobby. A universal yearning: more color to enliven and warm spaces now deemed austere and cold. Another consensus: greenery on the first-floor plaza. Food, coffee, wireless Internet access, shopping, lectures and classes, and an arts bookstore are just a few of the uses the public cites as attractions that would draw them. Those uses must be available on a visible, consistent basis.

4. Offer a warmer welcome - and a map to navigate. Convey to visitors that the center sees them as guests to be welcomed, not interlopers to be handled. The entry spaces should express that the center's core client is the public, not just large donors. Signs and posters should offer an array of Do's, not a list of Don't's. Take advantage of technology (iPods, LED screens, interactive kiosks) to give visitors information about what the center offers and how to use it. The building can be confusing; offer more guidance on how to get around it.

5. Wow! What now? Though grand and impressive, Commonwealth Plaza doesn't make it easy for people to linger. Create nooks, clusters of comfortable seating conducive to conversation. Make better use of dead-end hallways.

6. Balance aesthetic values and commercial appeal: Efforts to enliven Commonwealth Plaza and attract a broader public should not sacrifice the Kimmel Center's core values: world-class artistry, quality, taste and elegance.