A jackhammer reduced prototypes of President Donald Trump’s prized border wall into piles of rubble Wednesday, a quick ending to an experiment that turned into a spectacle at times.

The four concrete and four steel panels, spaced closely together steps from an existing barrier separating San Diego and Tijuana, Mexico, instantly became powerful symbols associated with the president and one of his top priorities when they went up 16 months ago.

For Trump’s allies, the towering models were a show of his commitment to border security and making good on a core campaign promise. For detractors, they were monuments to wasted taxpayer dollars and a misguided display of aggression toward Mexico and immigrants seeking a new home in the United States.

Within about two hours, a hydraulic jackhammer on an excavator leveled seven prototypes. Concrete slabs crashed in small clouds of dust, steel panels were knocked over, and an owl flew out of a steel tube atop one panel just before it thundered down. The last prototype standing took a little more time to destroy.

U.S. officials say elements of the prototypes have been melded into current border fence designs and they were no longer needed.

Public access to the prototypes was blocked from the San Diego side, turning an impoverished Tijuana neighborhood into a popular spot for journalists, anti-wall demonstrators and curious observers. People climbed piles of trash against a short border fence that has since been replaced to get a clear view from Mexico.

Artists projected light shows on the walls from Mexico, with one message reading “Refugees Welcome Here” next to an image of the Statue of Liberty and another showing a silhouette jumping on a trampoline with a caption that read, “Use in Case of Wall.” Demonstrators craned their necks for a view when Trump toured the prototypes 11 months ago.

Removal of prototypes made way to extend a second-layer barrier of steel poles topped by a metal plate rising 30 feet (9.1 meters) from the ground, the same design being used elsewhere on the border. The new barrier vaguely resembles some of the steel prototypes but looks nothing like the solid concrete panels, which were widely panned because border agents couldn’t see what was happening on the other side.

The nearly $3 billion that Congress has provided for barriers during the first half of Trump’s term requires that money be spent on designs that were in place before May 2017, effectively prohibiting the prototypes from being used and denying Trump bragging rights to say he built his wall. It’s unclear if the restriction would apply to the billions of dollars that Trump wants to spend by declaring a national emergency on the nation’s southern border, which the House of Representatives voted this week to block.

The eight prototypes, which cost $300,000 to $500,000 each to build, vary by slopes, thickness and curves. Bidding guidelines called from them to withstand at least an hour of punishment from a sledgehammer, pickaxe, torch, chisel or battery-operated tools and to prevent use of climbing aids such as grappling hooks.

The guidelines also required they be “aesthetically pleasing” from the U.S. side. One had two shades of blue with white trim. The others were gray, tan or brown — in sync with the desert.

The Department of Homeland Security redirected $20 million from its budget in February 2017, a month after Trump took office, to pay for the prototypes and smaller mock-ups built farther from the border that have also been dismantled. Open bidding generated a wide range of ideas, some of them whimsical or far-fetched. One bidder wanted a wall large enough for a deck that would offer tourists scenic views of the desert.

Bidders met fierce criticism from wall opponents. The Roman Catholic Archdiocese of Mexico said any Mexican companies that expressed interest were betraying their country.

The government rigorously tested the designs and, according to a summary from the Government Accountability Office, found that the concrete walls posed “extensive” construction challenges and the others posed “substantial” or “moderate” challenges. Six of the eight would require extensive changes to accommodate drainage.

A Customs and Border Protection report, first reported by KPBS of San Diego, showed that each prototype could be breached using several different techniques but the heavily redacted version that was made public did not say how long it took.

Ross Wilkin, a Border Patrol spokesman, noted that authorities never claimed the prototypes would be impenetrable and that they simply wanted to know how much time it took to crack each one.

The appeal to private industry for ideas was a new approach to building barriers and provided many lessons to guide construction, he said. Authorities learned that certain materials were unsuitable for quick repairs and that combining different surfaces, like bollards topped by plates, were more effective.

A steel model with vertical U-shaped indentations could be jammed with pieces of wood and become a ladder, Wilkin said. Prototypes with exposed fasteners — like screws or bolts — could be broken with the right tools.

“They were tested and evaluated,” Wilkin said. “They’re not required anymore. It’s time for them to go.”

The new barrier replaces a steel-mesh fence that runs more than 12 miles (19 kilometers) from the Pacific Ocean, which worked like a fortress when it was built a decade ago but is now regularly breached with powerful battery-operated saws recently made available in home improvement stores. It will then extend another mile or so over the prototype site. SLSCO Ltd. of Galveston, Texas, won the $101 million contract in December and started work last week.

Work on replacing the first-layer barrier, also with steel bollards and metal plates up to 30 feet high, runs the same length as the second layer and is nearly finished.

Illegal crossings have fallen dramatically in San Diego over the last 25 years as the government erected barriers and added agents. In the Tijuana neighborhood near the prototypes, Guillermina Fernandez briefly turned her patio into an informal restaurant about 15 years ago, once serving 200 sandwiches on a single order from a smuggler who fed his customers.

Smugglers dug small holes under the old fence for migrants to pass. Campfires warmed them while waiting for an opening to dart past border agents.

“It looked like a party here,” said Fernandez, 54, who, like some neighbors, built her shack of plywood scraps on squatted land that she and her husband later bought.

Residents complain that outsiders illegally dump trash on their dirt roads that lack street lights. They tout one benefit of the new wall: The poles allow the Border Patrol’s bright lights to seep in and provide some visibility at night.

(AP)