class Sup
     @@x = "A"
     def test 
      print @@x 
     end
    end
    
    class Sub1 < Sup
     @@x = "B"
    end
    
    class Sub2 < Sup
     @@x = "C"
    end
    
    Sup.new.test
    Sub1.new.test
    Sub2.new.test


I expect this to print "ABC", and yet it prints "CCC". Why is this?