They’ve provided a concrete-and-steel backdrop to President Trump’s relentless push to build a migrant-stopping wall on the U.S.-Mexico border. But the eight giant prototype walls erected near the Southern California border in 2017 are no more.

The 30 foot-by-30 foot segments were demolished in a matter of hours today by workers using a large hydraulic jackhammer and other equipment.

Each of the prototype walls cost from $300,000 to $500,000 to construct.

“Border Patrol spokesman Ross Wilkin said testing … exposed several design flaws,” reports the Associated Press. “A steel model with vertical U-shaped indentations could be jammed with small pieces of wood that could be climbed like a ladder. Prototypes with any exposed fasteners — like screws or bolts — could be broken with the right tools.”

Destruction of the prototypes makes way for a 30-foot-high barrier of steel bollards topped with metal plates, now under construction from the Pacific Ocean south of San Diego for 15 miles inland along the border, crossing the prototype site.

“Much of the material from the prototypes will be ground up and used as ‘fill’ in areas along the construction project,” reports the San Diego Union-Tribune.

“Public access to the prototypes was blocked from the San Diego side, turning an impoverished Tijuana neighborhood into a popular spot for journalists, demonstrators and curious observers,” says the AP. “Artists displayed light shows on the walls with messages such as ‘Refugees Welcome Here’ next to an image of the Statue of Liberty.”

The AP notes that “The prototypes are coming down during the same week the House voted to block Trump’s emergency declaration” of a border crisis, in order to use military and other government funds to build hundreds of miles of wall.