The book was likely finished sometime in late 1987 or early 1988]. II.The collapse of Communism in the Balkans. It is likely that Gorbachevâs ideas for liberalizing East European communist states worked out best in the Balkan states of Bulgaria and Romania.
A polygon is a  closed plane figure made of three or more straight line segments. The term originated from ancient Greek polygonon, which breaks down to polus (many) and gonia (angle). A polygon is a closed plane figure made of three or more straight line segments.
A polygon can be defined as a closed plane figure (a two dimensional shape) that consists of three or more line segments. Polygons can be divided into many types. One such type is based on the internal angles. A convex polygon is the one in which none of the angles point inwards. In other words, it has no internal angle that is greater than 180 degrees. A polygon with any of the internal angles greater than 180 degrees is known as a concave polygon.