The poetic form of dylan thomas' 'do not go gentle into that good nigh' is uncommon in the english language. what is the name of this form and why is it uncommon?

Read the passage below and answer the question that follows. ‘you make me feel uncivilized, daisy,’ i confessed on my second glass of corky but rather impressive claret. ‘can’t you talk about crops or something? ’ i meant nothing in particular by this remark but it was taken up in an unexpected way. ‘civilization’s going to pieces,’ broke out tom violently. ‘i’ve gotten to be a terrible pessimist about things. have you read ‘the rise of the coloured empires’ by this man goddard? ’ ‘why, no,’ i answered, rather surprised by his tone. ‘well, it’s a fine book, and everybody ought to read it. the idea is if we don’t look out the white race will be—will be utterly submerged. it’s all scientific stuff; it’s been proved.’ in this passage, tom’s ideas about race relations come off as uncivilized. what literary device is fitzgerald using here?