Polygon is simple closed circuit made by joining a finite number of line segments.

**Simple Polygon**

We call a polygon “simple” when NO line segments of polygon intersect each other.

**Complex Polygon**

We call a polygon “complex” when line segments of polygon intersect each other.

**Convex Polygon**

If we just consider two point inside polygon and try to join them using a line segment and if the line segment do not lie outside the polygon then we call such a polygon “convex”. NO angle of polygon is greater than 180 degree in convex polygon.

**Concave Polygon**

If we just consider two point inside polygon and try to join them using a line segment and if the line segment do lie outside the polygon then we call such a polygon “concave”. One or more than one angle of polygon is greater than 180 degree in concave polygon.