private void biasForFriend() {
    Vertex f = Vertex.vertexFromEmployee(Employee.getEmployeeFromId(ProjectParams.FRIEND_ID));

    List<Vertex> neighbors = f.getNeighbors();
    for (Vertex v : neighbors) {
      if (flowsForward(v, f)) {
        v.moveToFrontOfNeighbors(f);
      } else {
        v.moveToBackOfNeighbors(f);
      }
    }
  }