Time, Real and Imaginary — Samuel Taylor Coleridge

On the wide level of a mountain's head,(I knew not where, but 'twas some faery place)Their pinions, ostrich-like for sails outspread,Two lovely children run an endless race,A sister and a brother!This far outstript the other;Yet ever runs she with reverted face,And looks and listens for the boy behind:For he, alas! is blind!O'er rough and smooth, with even step he pass'd,And knows not whether he be first or last.