This tool is for demonstrating weighted graph algorithms. You can 
            
                - Add a vertex 
                    by clicking the primary button in an open area. 
- 
                    Remove a vertex by clicking 
                    at the vertex using the secondary button. 
- 
                    Add an edge between 
                    two vertices by dragging from one vertex to 
                    the other vertex. The weight is the distance between the vertices.
                
- 
                    Move a vertex by dragging the vertex while pressing
                    the CTRL button.