I might think that just as in the armpiece there is one parchment, so, should there be in the headpiece. And this would follow, viz.: Since the Torah prescribes tefillin (leather phylacteries worn during prayer) for both the hand and for the head, then just as in the handpiece there is one parchment, so, should there be in the headpiece. It is, therefore, written four times (in respect to the headpiece) "letotafoth." But in that case perhaps one should make four headpieces of four sections each? It is, therefore, written (Ibid.) "and as a memorial between your eyes." One compartment for four sections.