digraph Memory {
  rankdir=RL;
  node [shape=box];
  M [label="Default memory"];
  X [label="Store x"];
  Y [label="Store y"];
  X -> M [color=blue]; Y -> M [color=green];
  MemMerge -> M [label="default"]; MemMerge -> X [label="x",color=blue];
  MemMerge -> Y [label="y",color=green]; Return -> MemMerge;
}