code: function() {
              var polygonArea = 0;
              this.sides.map(function(side) {
                  polygonArea += side.vertex0.pos.cross(side.vertex1.pos);
              });
              polygonArea *= 0.5;
              return polygonArea;
          }
docs: see http://local.wasp.uwa.edu.au/~pbourke/geometry/polyarea/ : Area of the polygon. For a counter clockwise rotating polygon the area is positive, otherwise negative Note(bebbi): this looks wrong. See polygon getArea()