Figure 5: path finding with A*;
a.: case S: start from vertex S, potential next graph nodes are the
vertices marked with red arrows (assuming T is not on any neighbor
- vertex on this drawing)
+ vertex on this drawing)
b.: thick blue line is the path crossing the left edge of a triangle;
since the triangle contains the end vertex T, the only one next node
is T and the path is completed (thin blue line).