a flickering light

'This way and that
He let his mind run, passing quickly over
All he might do, as when from basins full
Of unstilled water, struck by a ray of sun
Or the bright disk of the moon, a flickering light
Plays over walls and corners and flies up
To hit the high roofbeams and a coffered ceiling.'

'Virgil, The Aeneid, between 29 and 19 BCE, translated by Robert Fitzgerald, 1983.