How to create nested box in PlantUML?

Question

I cannot make a nested box in plantUML.

@startuml
box "B0" #LightBlue
 Bob -> Alice : hello
 Box "B1" #LightYellow
  Bob --> Cunny : hi
 end box
end box
@enduml

This gives an error that box cannot be nested.

Any other way to show nested box, like in layered diagrams?

Answer 1

It seems it's still not supported: http://forum.plantuml.net/6304/please-add-box-and-or-participant-nesting-ability

You can up-vote the feature request.