heaped vs piled

heaped

adj
  • Containing a heap. 

  • In a heap. 

piled

adj
  • Formed from a pile or fagot. 

  • Having a pile or point; pointed. 

  • Having a pile or nap. 

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