To be precise, let $\Omega$ be an inaccessible cardinal in $L$ and let N be the Solovay model defined by the Levy-collapse in this case. Then $\Omega$ is $\aleph_1$ in $N$.
How many different OD (=ordinal-definable) sets of reals are there in $N$?
One answers that there is exactly $\aleph_2$ of them.
Now, is there a concrete, meaningful OD sequence of $\aleph_2$ different OD sets of reals in $N$?