intertwine vs unravel

intertwine

verb
  • To twine something together. 

  • To become twined together; to become mutually involved. 

unravel

verb
  • To become separated; (of something woven, knitted, etc.) to come apart. 

  • To separate the threads (of); disentangle. 

  • To separate the connected or united parts of; to throw into disorder; to confuse. 

  • To clear from complication or difficulty; to unfold; to solve. 

  • To become undone; to collapse. 

How often have the words intertwine and unravel occurred in a corpus of books? (source: Google Ngram Viewer )