The west wall of the Pentagon is flawless these days. Gone is any sign that a highjacked airliner crashed through the limestone and concrete and exploded, killing 189 people. 

To Jim Lachak, the reconstructed face of the building stands like a false symbol of a world gone back to the way it was on Sept. 10, when his brother, Dave, worked as a civilian for the Army in an office that lay in the direct line of fire. 

"There is no 'normalcy,"' Lachak says. "I'm afraid that 10, 15 years from now, people are going to be driving by and can't remember what side it was." 

Lachak and some other relatives of those who died in the Sept. 11 attack are making suggestions to the Army Corps of Engineers about a memorial. Some 1,600 people already have met Friday's deadline to register for a design competition. Proposals must be submitted by Sept. 11, with a winner announced on Dec. 23. 

"We challenge you to create a memorial that translates this terrible tragedy into a place of solace, peace and healing," families of the victims said in a statement to entrants. 

"Visitors should comprehend that our loved ones were murdered simply because they were living and working in, and enjoying the benefits of, a free society," they wrote. "The memorial should instill the ideas that patriotism is a moral duty, that freedom comes at a price, and that the victims of this attack have paid the ultimate price." 

Under the Corps plan, the winning design will occupy nearly two acres about 165 feet west of the point where American Airlines Flight 77 slammed into the facade. The attack killed 189 people — 125 in the Pentagon and 64 aboard the plane — and injured 110 at the Defense Department headquarters. The remains of the five hijackers on the flight have been separated from those of the victims. 

Advised by the families, memorial organizers have kept secret the few designs received so far, project manager Carol Anderson-Austra said. 

The winning design cannot rise above 78 feet — the Pentagon's height — and cannot interfere with the flight path to Reagan Washington National Airport. 

The memorial cannot include restrooms, museums or staff. It must incorporate security measures to keep visitors away from the Pentagon, be accessible to the public and be built under the flight path of Flight 77. The judges won't know the names of the entrants. 

For Lachak, the memorial will serve as a counterpoint to the Pentagon's reconstruction. 

"It's a cemetery, it's hallowed ground," he said. "I want it to be a place where the families and everybody can go and feel the sense of loss, but still come away with a sense of hope." 

It is not an easy assignment: conveying enormous loss and patriotism, heartbreak and inspiration, and in an appropriate context on a site sandwiched between the plane's impact and a highway interchange. 

Harvard-trained architect Simon Aldridge thinks he has the answer. 

Aldridge had not yet left home for his 92nd-floor studio in the World Trade Center when the first plane struck the twin towers on Sept 11. His colleague, Michael Richards, was killed and much artwork lost. 

"I have a definitive perspective on what the Pentagon memorial should be, and a unique empathy for the families," he wrote in an e-mail. He said he wants to create "both an appropriate memorial to the victims at the Pentagon and a moving monument to life, liberty and the pursuit of happiness." 

Reflecting the global effect of the attacks, registrations have come from all 50 states except South Dakota, as well as from Europe, Asia, Africa, Australia and South America, organizers say. 

Some competitors said they hope to help themselves and the world heal. 

"I feel compelled to somehow be involved in the emotional and physical reconstruction process in the aftermath of Sept. 11," Loraine Fowlow, a professor of architecture at the University of Calgary, wrote in an e-mail. 

Said Amber Wetzel of Cabin John, Md.: "I hope the final design shows the viewer that this nation is not impenetrable." 

Memorials also are being contemplated for the New York and Pennsylvania sites where the other hijacked planes struck. 

In New York, the Lower Manhattan Development Corp. is soliciting new designs for the World Trade Center site, where 2,819 people were killed when two planes hit the buildings. Officials in Shanksville, Pa., are awaiting congressional approval for a memorial to the 40 passengers and crew members who died when United Flight 93 crashed into a field.