digraph G {
	hello_world -> {foo_o bar_o} [dir="back"];
	foo_o [label="foo.o"];
	bar_o [label="bar.o"];
	foo_c [label="foo.c"];
	bar_c [label="bar.c"];
	foo_h [label="foo.h"];
	foo_o -> {foo_c foo_h} [dir="back"];
	bar_o -> {bar_c foo_h} [dir="back"];
}
