contrive vs knock together

contrive

verb
  • To invent by an exercise of ingenuity; to devise 

  • To invent, to make devices; to form designs especially by improvisation. 

  • To project, cast, or set forth, as in a projection of light. 

knock together

verb
  • To assemble something quickly; to knock up. 

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