c# - Access levels within namespace

Class   Constructor    Another Class
default   default   not accessible(cannot 
                    create object)main door(class) is default opened 
                    for others within namespace but not 
                    the room door(constructor) 
                    so they cannot open it.

default   public    accessible(can create object) - main 
                    door(class) is default opened for others and you 
                    have opened room door(constructor) also so 
                    accessible.

public    default   not accessible - you made main door(class) 
                    open not only for classes within the namespace but 
                    also for others outside the namespace but you have 
                    not opened the room doors so on one can access it.

public    public    accessible - Yep Congratulations you have 
                    opened the main 
                    door and also the room door so its accessible.

Caution: Be careful you can loose privacy in the last case