instance variable vs class variable

class App
    $super_count = 111
    @@count = 0
 
    def initialize (caller)
       @call = caller
    end
 
    # instance method
    def callme
        p “called using #{@call}”
        @@count+=1
    end
 
    # class method
    def App.callmetoo
        p “called using callmetoo”
        @@count+=1
    end
 
end
 
obj1 = App.new(”OBJECT1″)
obj2 = App.new(”OBJECT2″)
p obj1.callme
p obj2.callme
p App.callmetoo
p $super_count #can be access outside the class
#p App.@@count #cant access outside the class