Plato, Republic, book 10 135:

εἶναι, αὐτόσ τε οὐκ ἐπαί̈ων περὶ σκυτοτομίασ καὶ τοῖσ μὴ ἐπαί̈ουσιν, ἐκ τῶν χρωμάτων δὲ καὶ σχημάτων θεωροῦσιν;