@startuml
interface BiosInterface {
    +execute()
    +waitForKeyPress()
    +launch(OsInterface $os)
    +powerDown()
}

class Facade {
    #$os : OsInterface
    #$bios : BiosInterface
    +__construct(BiosInterface $bios, OsInterface $os)
    +turnOn()
    +turnOff()
}

interface OsInterface {
    +halt()
}
@enduml