@startuml
skin rose
skinparam BackgroundColor transparent
skinparam GenericDisplay old
skinparam componentStyle rectangle
' skinparam Shadowing false
hide members
left to right direction

component "List<Dog>" as ListDog
component "IEnumerable<Dog>" as IEnumerableDog {
    component "List<Dog>" as ListDogInner
}

component "IEnumerable<Animal>" as IEnumerableAnimal {
    component "IEnumerable<Dog>" as IEnumerableDogInner {
        component "List<Dog>" as ListDogInner2
    }
}

() " " as DogIterator
() " " as AnimalIterator

together {
component "Action<Dog>" as ActionDogContainer {
    component "Action<Animal>" as ActionAnimalInner
}
component "Action<Animal>" as ActionAnimal
component "Action<Dog>" as ActionDog
}


' Control layout
ActionDogContainer -[hidden]> ActionDog
ActionDog -[hidden]> ActionAnimal


ActionDogContainer --> ActionAnimalInner

ListDog --> DogIterator : iterate Dogs
ListDogInner --> IEnumerableDog : iterate Dogs
IEnumerableDog --> DogIterator : iterate Dogs

DogIterator --> ActionDogContainer : accept Dog
DogIterator --> ActionDog : accept Dog
DogIterator --> ActionAnimal : "\naccept Dog"


ListDogInner2 --> IEnumerableDogInner : iterate Dogs
IEnumerableDogInner --> IEnumerableAnimal : iterate Dogs
IEnumerableAnimal --> AnimalIterator : iterate Animals

AnimalIterator --> ActionAnimal : accept Animal

@enduml