Boundary Wall was a project completed for the Sculpture Center in Long Island City, NY December 2004-April 2005. 

'Crenellated Boundary Wall creates a porous barrier out of the invisible –and highly regulated- frequencies of the radio spectrum. Installed are forty-six forms (dentals) along the top of our sculpture yard’s 130-foot-long concrete wall, turning it into a medieval crenellated fortress. Each form is painted in stripes and blocks of bright colors, -a color code corresponding to a visualization of the various categories of U.S. radio frequency allocations: public safety, government, broadcast, cellular, marine, etc.  Installed atop the fifteen-foot-tall wall, the crenellations conflate obsolete defensive architecture, with the management of dematerialized boundaries, to frame a contained and controlled space infiltrated by people and information.'

http://www.sculpture-center.org/exhibitionsExhibition.htm?id=10109