"πάντα χωρεῖ καὶ οὐδὲν μένει" καὶ "δὶς ἐς τὸν αὐτὸν ποταμὸν οὐκ ἂν ἐμβαίης"
"Everything changes and nothing remains still ... and ... you cannot step twice into the same stream"

-Heraclitus