The fledgling Leonardo at Library Square is being touted by organizers as the cutting edge in museums, an arts-science-culture amalgam filled to the brim with interactive, constantly changing exhibits.

But the biggest showcase of all may be the building itself.

Leonardo executive director Mary Tull, after winning approval for the design from the Salt Lake City Council Thursday, said the plan is to "make the building an exhibit itself."

The Leonardo has finally settled on a seismic retrofitting plan for the building — the former main branch of the city library at the corner of 200 East and 500 South — after scrapping two earlier plans.

One of those plans was too costly, at $18 million and growing, and the other was aesthetically unpopular, with large exterior concrete braces buttressing the building on each corner.

The new design calls for four heavy-duty walls inside the building, tucked in the corners so they don't close off the interior atrium. It comes in at $13 million and changes nothing on the outside of the building.

So instead of changing the look of the exterior, organizers will change its use.

The concrete panels on the building's north, viewed from Library Square, will become canvases, covered in banners, light projections and other visually dramatic displays.

From the south, passers-by on 500 South will gaze through the large glass windows at artists participating in the museum's workshops and classes.

And as visitors enter the building, an evaporative tower will give the building functional, energy-efficient cooling while showcasing the science behind sustainable practices — as well as the cultural elements of environmental consciousness and some artistic flourishes to boot.

Inside, exhibits will vary from displays of Utah's history and cultures to the latest traveling shows. Tull suggested the Leonardo could one day host such exhibits as Bodies ... The Exhibition, a controversial showcase of real human bodies preserved to show how they work inside and out.

"We're developing a whole new model in the museum world," Tull said.

The City Council, acting Thursday as the board of directors for the city's Redevelopment Agency, approved extending the terms of a $750,000 grant it approved six months ago. That grant was approved when the design was still up in the air, and the debate centered over whether to go with the cheaper corner buttresses or a more expensive new north wing that would stabilize the building.

At the time, the council sent Leonardo staff on an intense fund-raising drive to see if they could come up with the shortfalls in funding. When it was clear that would not happen, "We went back to the architects and said, 'You've got to have an Option C,"' Tull said.