What is the theme in Answers to Letters by Tomas Transtromer?

Many of Tranströmer's central thematic concerns in "Answers to Letters" are related to time. This is most explicit in the third stanza and its description of the speaker's experience of the labyrinth of time, but each stanza refers to time in some manner, often in connection to the speaker's memory and past represented by the rediscovered letter. Stanza one introduces the theme of an object representing something twenty-six years in the past that is still breathing and panicking; stanza two seems to refer to some obscure and cloudy version of time outside its "fifth window"; stanza four describes time in unique visual terms emphasizing that it does not run in a straight line; and stanza five envisions the speaker in a contradiction between a vague point in time in the future ("one day"), and the specific moment of walking in the wind of 125th street.