χειροστρόφιον
From LSJ
Δελφῖνα νήχεσθαι διδάσκεις: ἐπὶ τῶν ἐν ἐκείνοις τινὰ παιδοτριβούντων, ἐν οἷς ἤσκηται → Teaching dolphins to swim: is applied to those who are teaching something among people who are already well versed in it
English (LSJ)
τό,
A instrument of torture for twisting the hands or arms, Hdn.Epim. 150.
German (Pape)
[Seite 1346] Marterwerkzeug, die Hände oder Arme zu verdrehen, Hdn. epimer. 150.
