It functions as a wonderful mix of the mechanical and the organic, as a steady drum machine and languid pedal steel ring out side by side.

NPR: Heartfelt Emotion in an Orchestral Arrangement

He worries that the ring of steel will not deter attackers, but merely force them to change targets.

ECONOMIST: New York expands its counterterrorism monitoring system

All week in Mexico City, a ring of steel had been in place around the building ahead of the ceremony.

BBC: Mexico's Enrique Pena Nieto inaugurated as president

The NYPD also maintains a "Ring of Steel, " a network of 4, 000 sophisticated security cameras that feed information into a central monitoring system to detect questionable or unlawful activity.

WSJ: Judith Miller: How to Stop Terrorists Before They Kill

It is possible that there is a ring of steel just out of shot, but it seems that the students only close in on the police after the pepper spraying, rather than before, and then pull back voluntarily to allow the officers to reach the safety of their support.

FORBES: PR and Pepper Spray: What the 99% Can Teach Companies

Rather than using rubber hoses to connect the stationary and moving parts of the building, 3sixty's ingenious plumbing system employs horizontal ring-shaped pipes made of steel.

ECONOMIST: Monitor