singleton_instance_var_fuckery.rb

class SC
  def self.set_var(val)
    @var = val
  end

  def superclass_instance_get_var
    puts self.class.instance_variable_get("@var")
  end

  def self.superclass_class_get_var
    puts instance_variable_get("@var")
  end
end

class C < SC
  set_var "foo"

  def subclass_instance_get_var
    puts self.class.instance_variable_get("@var")
  end

  def self.subclass_class_get_var
    puts instance_variable_get("@var")
  end
end

C.new.subclass_instance_variable_get
C.subclass_class_get_var
C.new.superclass_instance_get_var
C.superclass_class_get_var