Use the left
mouse button to create the graph nodes within the light area. Click on two
existing nodes, first source then destination, to make an edge between them.
A marked node will be unmarked by clicking on it again. If one node is
marked and a mouse click is done outside any node, a new node at this
place will be created along with an edge to it from the marked one.
Any click on a node with the right mouse button starts the algorithm with
the root at this node. The shortest paths from the root are shown in red color.
Click the Reload button of your browser to start over and let the applet
take the whole space after resizing the window.