Rotated Border Wall
This is a proposal for a 1,500 mile wall that is rotated 90 degrees at its midpoint. It is 3D printed in bioconcrete from a fabrication satellite in geosynchronous orbit above the New Mexico / Mexico border. It absorbs CO2 and harmful pollutants that are immigrating into our atmosphere. It is also an antenna for alien intelligence.
The orthogonal rotation transforms the border wall from an expression of Westphalian nation-state boundaries to a mediator between Earth and its proximate entities.