Free verse is the most popular poetic form used by twentieth and early twenty-first century poets, and it is the form Castillo uses in writing "While I Was Gone a War Began." Walt Whitman was perhaps the first poet to use this form, and it was quite a shock to readers in 1855 who were used to poems with strict metrical and rhyme patterns (for example, sonnets). Free verse avoids patterns and fixed line lengths.
While I Was Gone a War Began