ποταμῷ γὰρ οὐκ ἔστιν ἐμβῆναι δὶς τῷ αὐτῷ → it is impossible to step twice in the same river, you cannot step twice into the same rivers
ἵδρυμα, ἵδρυσις, ἀναπομπή, οἰκοδόμησις