Still confused:
```ruby
class Foo
  class << self
    def static
      @@var_a = 1
      @var_b = 2
    end
  end
end
Foo.static
puts "@@var_a #{Foo.class_variable_get(:@@var_a)}"
puts "@@var_b #{Foo.class_variable_get(:@@var_b) rescue NameError}"
puts "@var_a  #{Foo.instance_variable_get(:@var_a)}"
puts "@var_a  #{Foo.instance_variable_get(:@var_b)}"
```

Returns

```bash
@@var_a 1
@@var_b NameError
@var_a  
@var_a  2
```