user { # User
  n1: circle label:"Start Escalation Pattern"
  n4: rectangle label:"Execute Escalation Pattern action"
  n7: rectangle label:"Monitor Escalation Pattern status"
  n10: circle label:"End Escalation Pattern"
  n1.handle(bottom) -> app.n2.handle(top)
  n4.handle(bottom) -> app.n5.handle(top)
  n7.handle(bottom) -> app.n8.handle(top)
}

app { # App
  n2: rectangle label:"Receive Escalation Pattern event"
  n5: rectangle label:"Record Escalation Pattern outcome"
  n8: rectangle label:"Monitor Escalation Pattern status"
  n2.handle(bottom) -> service.n3.handle(top)
  n5.handle(bottom) -> service.n6.handle(top)
  n8.handle(bottom) -> service.n9.handle(top)
}

service { # Service
  n3: rectangle label:"Validate Escalation Pattern conditions"
  n6: rectangle label:"Monitor Escalation Pattern status"
  n9: diamond label:"Monitor Escalation Pattern status"
  n3.handle(right) -> user.n4.handle(left) [label="Processed"]
  n9.handle(left) -> app.n8.handle(left) [label="Retry/Rejected"]
  n9.handle(right) -> user.n10.handle(bottom) [label="Valid"]
  n6.handle(right) -> user.n7.handle(left) [label="Success"]
}