figure-4.dot

digraph {
  node [shape=circle,width=1.25];
  A[label="A\nMIT"];
  B[label="B\nProsperity"];
  C[label="C\nBlue Oak\nProsperity"];
  D[label="D\nParity\nBlue Oak"];
  A -> B, C;
  C -> D;
}