Endless Tasks

The Cyclopes knew them only too well:

ἐν μὲν ἔσαν Κύκλωπες ἐπ᾿ ἀφθίτῳ ἥμενοι ἔργῳ,
The Cyclopes were on it (Jason's cloak), seated at their endless task (making a thunderbolt for Zeus).
Apollonios of Rhodes 1.730.