Question: The "Maschinengewehr" 30 is most notable as the design pattern that led to what is generally considered the world's first what?
Context: PatternShare was a computer software design pattern web resource, hosted by Microsoft.  Much of the work was led by Ward Cunningham, of Microsoft.  In 2007 Pattern Share was taken offline. The "Iowa"-class battleships were a class of six fast battleships ordered by the United States Navy in 1939 and 1940 to escort the Fast Carrier Task Forces that would operate in the Pacific Theater of World War II.  Four were completed, two more were laid down but canceled in August 1945, at war's end, and both hulls were scrapped in 1958.  Like other third-generation American battleships, the "Iowa"s followed the design pattern set forth in the preceding "North Carolina"-class and "South Dakota"-class battleships, which emphasized speed in addition to secondary and anti-aircraft batteries.  Based on wartime experience, they were to serve as fast escorts for "Essex"-class aircraft carrier s. The war against Islam (also called war on Islam or attack on Islam) is a term used to describe acts of harm, weakening or annihilation committed against the religion of Islam or countries where Islam is widespread via military, economic, social and cultural means.  Generally considered to have started with the crusades, the perpetrators of the conspiracy are alleged to be "kuffār" or "munafiq", and generally considered to be in collusion with political actors in the Western world. Yosegi-zaiku (寄木細工 ) is a type of traditional Japanese marquetry which originated during Japan’s culturally rich Edo Period.  It has become widely known and respected throughout the world.  The mosaic work is made by making use of natural fine grains and textures of wood.  Timbers of different colors are cut into oblong rods of desired sections.  Spindle tree ("Euonymus" spp.)  and "Ilex macropoda" are used for white, aged Katsura tree ("Cercidiphyllum japonicum") for black, "Picrasma quassioides", mulberry ("Morus alba") and Chinese lacquer tree ("Toxicodendron vernicifluum") for yellow, camphor tree ("Cinnamomum camphora") and "Maackia" for brown, black walnut ("Juglans nigra") for purple, Japanese cucumber tree ("Magnolia obovata") for blue and Chinese cedar ("Toona sinensis") for red.  The rods are then glued together to form the section of geometrical design pattern.  The sectional surface is sliced into thin plates of wood, which are glued onto boxes and other handicraft works.  To add to the glaze and sturdiness of the surface, finishing coatings of lacquer are applied. In object-oriented computer programming, a Null Object is an object with no referenced value or with defined neutral ("null") behavior.  The Null Object design pattern describes the uses of such objects and their behavior (or lack thereof).  It was first published in the "Pattern Languages of Program Design" book series. Presenter first is a software development approach that combines the ideas of the model–view–presenter (MVP) design pattern, test-driven development, and feature-driven development. The "Maschinengewehr" 34, or MG 34, is a German recoil-operated air-cooled machine gun, first tested in 1929, introduced in 1934, and issued to units in 1936.  It accepts the 7.92×57mm Mauser cartridge, and is generally considered the world's first general-purpose machine gun. In software engineering, double-checked locking (also known as "double-checked locking optimization") is a software design pattern used to reduce the overhead of acquiring a lock by first testing the locking criterion (the "lock hint") without actually acquiring the lock.  Only if the locking criterion check indicates that locking is required does the actual locking logic proceed. The "Maschinengewehr" 30, or MG 30 was a German-designed machine gun that saw some service with various armed forces in the 1930s.  It was also modified to become the standard German aircraft gun as the MG 15 and MG 17.  It is most notable as the design pattern that led to the MG 34 and MG 42, and thus is one of the major ancestors of many of the weapons in service which would later find widespread use into the 21st century. In parallel computing, the fork–join model is a way of setting up and executing parallel programs, such that execution branches off in parallel at designated points in the program, to "join" (merge) at a subsequent point and resume sequential execution.  Parallel sections may fork recursively until a certain task granularity is reached.  Fork–join can be considered a parallel design pattern.  It was formulated as early as 1963.
Answer: general-purpose machine gun