pattern, sometimes called T-pattern or T-block, consists of three gray tones arranged in a geometric pattern, intended as a 'pattern breaker' to make Marine troops harder to locate when in such environments. Like all modern BDUs, it is made of a lightweight rip-stop material. The pattern was never officially adopted, and it has since been superseded by MARPAT. History Exercises in Chicago, May 1998 Eighty Marines from 1st Battalion, 8th Marines, stationed in Marine Corps Base Camp Lejeune, toured Chicago to enhance knowledge of urban infrastructure, such as a gas plant, water facility, tunnels, bridges, and police and Fire stations. Exercises in the San Francisco East Bay, March 1999 A four-day military exercise was planned and executed in Oakland, California in March 1999. A combined force of 6,000 Marines and 700 sailors took control of the grounds and buildings of the defunct Oak Knoll Naval Hospital invaded the defunct Naval Air Station Alameda on the second day as part of a national effort called Operation Sea Dragon. After original plans to use the San Francisco Presidio were rejected by the National Park Service based on the size of the spectacle and its inherent environmental damage, and a trial run at the Naval Postgraduate School beach in Monterey, California, Oakland Mayor Jerry Brown and Alameda Mayor Ralph Appezzato welcomed the Marines to use their cities as a proving ground. The operations included numerous aviation assets, such as AV-8B Harrier IIs, CH-46 Sea Knights, CH-53 Sea Stallions, AH-1 SuperCobras, and UH-1N Twin Hueys, as well as several Landing Craft Air Cushion. Five Navy ships, including and ,were brought in and opened for public view during the operations. See also Low-intensity conflict Counter-insurgency Divide and rule Irregular warfare Urban warfare Fourth generation warfare Military operations other than war Hearts and Minds (Vietnam War) Hearts and minds (Iraq) Notes and references External links Urban Warrior, the movie Urban warfare United States Marine Corps in the 20th century