Stupid class variable "trick"

Stupid class variable tricks

bash$ irb
>> class Foo; @@foo = :foo; class << self; def inside_foo; @@foo; end end end
=> nil
>> class << Foo; def outside_foo; @@foo; end; def outside_get_foo; send(:class_variable_get, :@@foo); end end
=> nil
>> Foo.inside_foo
=> :foo
>> Foo.outside_foo
(irb):2: warning: class variable access from toplevel singleton method
NameError: uninitialized class variable @@foo in Object
        from (irb):2:in `outside_foo'
        from (irb):4
>> Foo.outside_get_foo
=> :foo