fit together vs superstruct

fit together

verb
  • To be able to be assembled in this way. 

  • To put the appropriate parts of (something) into a whole; to combine pieces that go together to create a finished object. 

superstruct

verb
  • To build over or upon (another structure); to erect upon (a foundation). 

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