digraph petrinet {
    PROGRAM_END [shape="circle" xlabel="PROGRAM_END" label=""];
    PROGRAM_PANIC [shape="circle" xlabel="PROGRAM_PANIC" label=""];
    PROGRAM_START [shape="circle" xlabel="PROGRAM_START" label="•"];
    main_RETURN [shape="box" xlabel="" label="main_RETURN"];
    PROGRAM_START -> main_RETURN;
    main_RETURN -> PROGRAM_END;
}