Math Trivia : Connect five points

The figure below is a diagram with a number of 1-5 at the apex of the symmetrical pentagon (not a regular pentagon).

Drawing a straight line starting from 1 and go along each point from 2 to 5 only once and return to 1. 

How many kinds of figure are made? 

The figure that can be overlapped is considered to be the same figure.

8 kinds