τὸν πυλῶνα καὶ τὸ ἐν αὐτῷ ἐμπέτασμα → the parodos gateway with its curtain
ob-turgesco: tursi, 3,I v. inch. n., to begin to swell, to swell up (very rare; not in Cic.): obturgescit pes, Lucr. 6, 658; Paul. ex Fest. s. v. bova, p. 30 Müll.: obtursi ebrius, Lucil. ap. Prisc. p. 870 P.
