PennaGroup's design for the Trump administration's border wall. PennaGroup PennaGroup, a construction firm in Fort Worth, Texas, imagines a wall made of wire and a one-way sheet of plexiglass.

The design competition for the wall asks for two prototypes: a solid concrete wall and “ other border wall ”, a category more open to alternative ideas.

Pointed tops. Fewer gates. Resistance to climbing. The president’s frequently changing design requests have frustrated Homeland Security officials and military engineers.

The Trump administration has accepted design proposals for the wall the president wants to build along the 2,000-mile border with Mexico. Some companies have radically different ideas.