blue-sky thinking vs masterminding

blue-sky thinking

noun
  • Thinking that is not grounded or in touch with the realities of the present; open-minded thinking. 

masterminding

noun
  • A creativity technique by which a group tries to find solutions for a specific problem from ideas spontaneously contributed by its members. 

How often have the words blue-sky thinking and masterminding occurred in a corpus of books? (source: Google Ngram Viewer )