You transform yourself at a whim, assuming whatever shape momentarily seizes your fancy, with a childish lack of discipline.

Every ten years or so, Busoni moves in from the margins of the repertory, momentarily seizes the attention of New York concertgoers, and then retreats into semi-obscurity.

The others had seemed either ignorant fanatics or avaricious opportunists, while the manner and speech of the Mexican had stamped him as a light-hearted soldier of fortune, who might gayly offer his life in any cause which momentarily seized his fancy with an eye more singly for excitement and adventure than for any serious purpose.

He fell backward, seized momentarily by terror.