On Sep 24, 2007, at 17:14 , SpringFlowers AutumnMoon wrote:

> Fixnum   object_id
> 0            1
> 1            3
> 2            5
>
> -1          -1
> -2          -3
>
>
> so the question is...  which objects have the object_id 2, 4, 6,  
> and -2,
> -4, etc?

ri ObjectSpace._id2ref

 >> (0..5).map { |n| ObjectSpace._id2ref(n) }
=> [false, 0, true, 1, nil, 2]