convolution vs twirl

convolution

noun
  • The shape of something rotating; a vortex. 

  • One 360° turn in a spring or similar helix. 

  • A mathematical operation on two functions that produces a third that expresses how the shape of one is modified by the other; the integral of the product of the two functions after one is reflected about the y-axis and shifted along the x-axis. 

  • Any of the folds on the surface of the brain. 

  • A twist or fold. 

  • The state or condition of being convoluted. 

  • A function which maps a tuple of sequences into a sequence of tuples. 

twirl

noun
  • Any rotating movement; a spin. 

  • A little twist of some substance; a swirl. 

  • A movement where a person spins round elegantly; a pirouette. 

  • A prison guard. 

verb
  • To twist round. 

  • To pitch. 

  • To rotate rapidly. 

  • To perform a twirl. 

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