polder vs quicksand

polder

noun
  • An area of ground reclaimed from a sea or lake by means of dikes. 

verb
  • To reclaim an area of ground from a sea or lake by means of dikes. 

quicksand

noun
  • Wet sand that appears firm but in which things readily sink, often found near rivers or coasts. 

  • Anything that pulls one down or buries one metaphorically 

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