@startuml
!include ../style.puml

skinparam ClassFontColor #000000
skinparam ClassBorderColor #000000

title After command "undo"

package States <<rectangle>> {
    class State1 as "__courseBook:CourseBook__"
    class State2 as "__backupCourseBook:CourseBook__"
}

State2 -[hidden]right-> State1
State1 -[hidden]right-> State3

hide State3

class Pointer as "Current State" #FFFFF

Pointer -up-> State2
@enduml
