DENVER (AP) _ Pieces of twisted metal found for blocks around the bombed Oklahoma City federal building could have come from the Ryder truck Timothy McVeigh allegedly rented to deliver the bomb, a truck expert testified today.

Edward Michael Paddock, a former Ford engineer, came into court with a Ryder truck that was cut into pieces to show jurors the parts. It was matched against the pieces of blackened and mangled metal found at the scene.

The axle from the demonstration truck matched the one that was hurled a block away by the blast, Paddock said.

The vehicle number from the mangled axle was used to trace it to the Ryder truck that a witness testified he rented to McVeigh two days before the April 19, 1995 bombing.

Prosecutors on Wednesday wheeled in hundreds of pounds of mangled truck parts that they say came from the Ryder truck, including tire rims, a gear and an 8-foot frame section. A parade of agents testified the parts were scattered on rooftops, streets and parking lots. In one case, part of the steering assembly was embedded in the side of a van.

Also today, Timothy McVeigh spoke audibly in court for the first time in weeks, saying ``Yes sir, I do'' when asked by the judge if he agreed not to contest some items of evidence.

Before the jury was called in, attorneys for both sides agreed to accept a sample of co-defendant Terry Nichols' handwriting, testimony that the South Dakota town listed on a fake driver's license used to rent the Ryder truck does not exist and testimony from McVeigh's brother-in-law that the defendant filled out a W-4 form to work as an apprentice electrician.

The most dramatic moment Wednesday came when jurors saw chilling black-and-white surveillance pictures of a Ryder truck moving toward the federal building minutes before a bomb blew the nine-story structure apart, killing 168 people and injuring more than 500.

Jurors sat grim-faced as they watched the stop-action video frames showing the street through the glass of the Regency Towers apartment complex a block from the federal building. The truck appears in the background of the frame, the word ``Ryder'' clearly visible, and then pulls away. The cab and the driver are whited-out by glare.

Richard Nichols, a maintenance employee at the Regency, choked back tears as he testified he could have been in front of the federal building at the time of the bombing. But he was running late for a meeting with his wife to take their nephew, Chad, to the doctor.

Surveillance pictures of the lobby show Nichols as he met his wife and walked out the doors, the final frame the camera took that day.

``I took about two steps when there was a terrific explosion,'' he testified. ``We felt heat and pressure and it kind of spun us around a little bit.

The couple were caught in a maelstrom of smoke, glass and chunks of cars and buildings as they tried frantically to unstrap the seat belt of their 10-year-old nephew.

``I seen this humongous object coming to us out the air. And it was spinning like a boomerang. And you could hear this `woo-woo-woo-woo' noise. And I looked and I seen it; and I told her _ I said, `Get down.'''

The Ryder truck axle smashed into the Ford Festiva's hood with his wife and nephew inside. No one was seriously injured, but his close call with the 7-foot-long, 250-pound piece of jagged metal left Nichols shaken.

``I grabbed my wife, and I grabbed Chad,'' he said, ``and I kind of hovered over them like an old mother hen.''

McVeigh, a 29-year-old Gulf War veteran, could get the death penalty if convicted of murder and conspiracy in the blast, the deadliest act of terrorism on U.S. soil. Prosecutors contend he wanted to retaliate for the FBI's deadly 1993 raid on the Branch Davidians near Waco, Texas.