Angle trisection an angle of measure 30 degrees). It is possible to trisect an arbitrary angle by using tools other than straightedge and compass. For example, neusis construction, also known to ancient Greeks, involves simultaneous sliding and rotation of a marked straightedge, which cannot be achieved with the original tools. Other techniques were developed by mathematicians over the centuries. Because it is defined in simple terms, but complex to prove unsolvable, the problem of angle trisection is a frequent subject of pseudomathematical attempts at solution by naive enthusiasts. These "solutions" often involve mistaken interpretations of the rules, or are simply incorrect. Using
Nambu Type 90 Nambu Type 90 The Nambu Type 90 was a flare gun of Japanese origin and manufactured by Nambu. It was used by the Imperial Japanese Navy and came with two or three barrels. The Type 90 designation is from the last two digits of its year of adoption, which was 2590 (or 1930 AD) on the Japanese "Kōki" calendar. It first came with three barrels with just less than 6,000 were manufactured. The First Model (made in the early 1930s during peacetime) was highly polished and finished, while the Second Model (dating from the mid-1930s to the mid-1940s during wartime)