An ELT Glossary : Parallel syntax

• Definition : The repetition of a sentence, clause or phrase structure within a piece of text,which helps to give cohesion to the text. It may be used for dramatic or rhetorical effect 

• Example  : "A small step for man, a giant step for mankind." (Neil Armstrong, as he stepped onto the moon for the first time)

• Example : "It was the best of times, it was the worst of times." (Dickens, A Tale of Two Cities)

• Political speeches will often use parallel syntax as a persuasive, rhetorical device (eg Barack Obama's Yes we can speech : We have been told we cannot do this by a chorus of cynics…. We've been asked to pause for a reality check. We've been warned against .. ). It's often found in advertisements for the same reason : Tastes more like Coke. Looks more like Coke  (Coca Cola Zero Sugar)