deadlock vs photo finish

deadlock

noun
  • A standstill resulting from the opposition of two evenly matched forces; a stalemate or impasse. 

  • An inability to continue due to two programs or devices each requiring a response from the other before completing an operation. 

verb
  • To cause or come to a deadlock. 

photo finish

noun
  • Any competition with a very close outcome. 

  • The finish of a race in which the leaders are so close together that the winner cannot be identified using the naked eye but is determined by means of a photograph. 

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