atha varṇās tirobhūtavyaktayo viditāḥ purā / smaryante 'vasthitā eva na spaṣṭābhaprasaṅgataḥ //
If the letters, whose manifestations are concealed, [were] previously known, [and if] they are remembered while [still] existing, [this leads to] the unwanted consequence of [their being] clear.