Editing Part number (section)

== Symmetrical parts ==
Many assemblies with [[reflection symmetry]], such as the fuselages and wings of aircraft, the hulls of ships and boats, and the bodies of cars and trucks, require matched pairs of parts that are identical, or nearly identical, except for being mirror images of each other. (For example, the left and right wings of an airplane, or the left and right fenders or doors of a car.) Often these related parts are designated '''left-hand''' ('''LH''') and '''right-hand''' ('''RH''') parts. It is a common practice to give them sequential [[#Dash numbers|dash numbers]], or -LH and -RH part number suffixes. It is also not uncommon to show only one of them on the drawing, and to define the symmetrical counterpart simply by stating that it is "opposite". Common notations include "left-hand shown, right-hand opposite" or "-1, LH (shown); -2, RH (opposite)".