@startuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response

Alice -> Bob: Another authentication Request
Alice <-- Bob: another authentication NEW
@endum
@startuml

    Class Stage
    Class Timeout {
        +constructor:function(cfg)
        +timeout:function(ctx)
        +overdue:function(ctx)
        +stage: Stage
    }
     Stage <|-- Timeout

@enduml

![Alt text](http://g.gravizo.com/g? digraph G { aize ="4,4"; main [shape=box]; main -> parse [weight=8]; parse -> execute; main -> init [style=dotted]; main -> cleanup; execute -> { make_string; printf}; init -> make_string; edge [color=red]; main -> printf [style=bold,label="100 times"]; make_string [label="make a string"]; node [shape=box,style=filled,color=".7 .3 1.0"]; execute -> compare; } )

![Alt text](http://g.gravizo.com/g? @startuml; actor User; participant "First Class" as A; participant "Second Class" as B; participant "Last Class" as C; User -> A: DoWork; activate A; A -> B: Create Request; activate B; B -> C: DoWork; activate C; C --> B: WorkDone; destroy C; B --> A: Request Created; deactivate B; A --> User: Done; deactivate A; @enduml )