Ever and anon

Ever and anon a bright, but, alas, deceptive idea would dart you through.

I could see Salemina at the far end of the table radiant with success, the W. S. at her side bending ever and anon to catch the (artificial) pearls of thought that dropped from her lips.

Ever and anon the guard's face could be dimly seen at his window, more like a ghost than a man; [...].

Pippin never forgot that hour in the great hall under the piercing eye of the Lord of Gondor, stabbed ever and anon by his shrewd questions