digraph finite_automata {
 /* graph properties */
 graph [rankdir=LR label="hw4.fa"];
 node [style=filled fillcolor="#E0E0E0"];
 /* states */
 q0 [shape=doublecircle];
 q1 [shape=circle];
 r0 [shape=circle];
 r1 [shape=circle];
 r2 [shape=doublecircle];
 s [shape=circle];
 invis_start [style=invis];
 /* transitions */
 invis_start -> s [label=" "];
 q0 -> q0 [label="1"];
 q0 -> q1 [label="0"];
 q1 -> q0 [label="0"];
 q1 -> q1 [label="1"];
 r0 -> r0 [label="0"];
 r0 -> r1 [label="1"];
 r1 -> r1 [label="0"];
 r1 -> r2 [label="1"];
 s -> q0 [label="~"];
 s -> r0 [label="~"];
}