A charred block of limestone and a steel time capsule remembering lives lost were set in the outer wall of the Pentagon yesterday, completing all exterior reconstruction work at the building nine months after the attack that killed 189 people.

Marking the passage of three-quarters of a year since the Sept. 11 attack with a simple ceremony, Pentagon officials said the reconstruction project remains ahead of schedule and more than $200 million below cost. Officials also announced a design competition for a Pentagon memorial on two acres adjacent to where the plane struck the building, a site that is now a staging area for construction crews.

At the morning ceremony, Deputy Defense Secretary Paul D. Wolfowitz supervised as a crane placed the last of 3,996 limestone slabs used in repairing the damaged west facade of the Pentagon.

"You've healed this wall, and in doing so, you are helping to heal our nation," Wolfowitz told cheering workers in construction helmets, who formed a semicircle around the building or stood on the crane or atop building supplies to watch the ceremony.

Carved on the stone, still blackened by fire from the attack, is a simple inscription: "September 11, 2001." Its dark face made a dramatic contrast to the bright new limestone, sent from the Indiana quarry that provided the original Pentagon facade.

"I was personally kind of shocked when I first saw it," W. Lee Evey, the Pentagon renovation manager, said yesterday. "I'd forgotten how dark and damaged the building was."

Behind the block, a steel time capsule was placed and sealed in the building, with no intention that it ever be opened. Inside were letters and cards sent to the Pentagon by children, a signed copy of President Bush's Sept. 20 speech declaring war on terrorism, and a bronze box with the names of 184 people killed Sept. 11 aboard the hijacked American Airlines jet or in the Pentagon. The names of the five hijackers were not included.

Many workers lined up by the charred limestone to pose for pictures holding the time capsule before it was sealed in the building.

Despite the buoyant mood, many agreed it was too soon to celebrate. "We're not quite there yet," said Brian Smith, a quality assurance manager on the reconstruction project. "When we have people in there, we'll feel a lot better. But it felt good to see that last stone go in."

A digital clock on a sign counted down the time left until the anniversary of the moment the jet struck the Pentagon: 91 days, 22 hours, 59 minutes and 32 seconds.

By then, Pentagon officials promise, employees will be working at their desks in the area closest to where the jet struck. Reoccupying all the damaged areas will take several months more, Evey said. Already, about 2,000 workers have moved back into offices damaged by smoke and water.

"Keeping rolling, that's all we're doing," said John Conrad, a telecommunications worker from Odenton. "Trying to get it done."

Last night, for the first time since the jet hit the Pentagon, the floodlights illuminating the west side of the building were shut off.

"The story outside the building is over," Evey said at a news conference yesterday. "The story now moves inside the building."

Evey, who three months ago projected the repair costs at $740 million, now estimates that the figure will be $501 million, of which about $400 million has been spent. Evey attributed the savings to price negotiations and effective performance by contractors.

The Pentagon was under renovation at the time of the attack, but instead of being delayed, the project has been accelerated by changes in the work process and increased support from Congress. The entire renovation is now projected to be completed by 2010, rather than 2014, Evey said.

Meanwhile, memorial organizers are planning a global design competition and expect to have a winner by year's end.

The site near the Pentagon's west face was chosen in consultation with family members, said Carol Anderson-Austra, a U.S. Army Corps of Engineers official serving as project manager. Organizers already have received several hundred inquiries about submitting designs, she said.

The deadline for submissions is Sept. 11. A nine-member jury -- including architects, landscape architects and a representative of the families -- will recommend a winner, though a final decision will be made by senior Pentagon officials, Anderson-Austra said.

Information will soon be available by calling a toll-free number, 1-866-782-4383, or on the memorial competition Web site, http://memorialcompetition.pentagon.mil.

As workers watch in window, Deputy Defense Secretary Paul D. Wolfowitz, standing, and renovation manager W. Lee Evey put time capsule into wall.Deputy Defense Secretary Wolfowitz lifts time capsule to be set into wall. At right is renovation manager Evey.Huy Ngoc Tran of Arlington, who does drafting design, watches yesterday's ceremonies, which marked nine months since the attack.