gml4gtk/data/task.gv

/* task depends on other tasks */
digraph "task"
{
 /* to complete task, do task1,2 and 4*/
 1[label="to complete\ntask"];
 2[label="do task1"];
 3[label="do task2"];
 4[label="do task4"];
 /* to complete task, first do task1 and task2 */
 1->2;
 1->3;
 /* to do task1 or task2 first do task4 */
 2->4;
 3->4;
}