digraph Memory {
  rankdir=LR;
  node [shape=box];
  M0 [label="Initial memory"];
  X [label="Store p.x = 3"];
  Y [label="Store p.y = arg"];
  L [label="Load p.x"];
  M0 -> X -> Y -> L [color=blue];
  Y -> Return [color=blue]; L -> Return;
}