A linear map is an isometric means following :

1.    T takes collinear points to collinear points, i.e. images of straight lines are straight lines
2.    T preserves division-ratios
3.    T  preserves distances

     The following applet describes all the isometrics of . To use applet proceed as follows :

• Click at some points on the left panel to form a polygon
• Choose a transformation
• See the image in the right panel