blend vs play by ear

blend

verb
  • To be mingled or mixed. 

  • To mingle; to mix; to unite intimately; to pass or shade insensibly into each other. 

noun
  • A mixture of two or more things. 

  • A word formed by combining two other words; a grammatical contamination, portmanteau word. 

play by ear

verb
  • To do by guessing, intuition, or trial and error; to react to events as they occur; improvise 

  • To play guided by one's musical ear, rather than from a written score. 

How often have the words blend and play by ear occurred in a corpus of books? (source: Google Ngram Viewer )