Draw a figure using only straight line pieces, without taking the pencil off the paper, until you return to the beginning without crossing the path. You drew a polygon! What is a polygon Definição · Polygon A polygon is a flat closed figure, formed only by pieces of straight lines (the sides) that do not intersect. The points where two sides meet are the vertices. The circle is not a polygon: its contour is curved. An open figure is also not a polygon.