acid test vs prototype

acid test

noun
  • A rigorous test or appraisal of the quality or worth of something. 

  • In the 1960s, a party based around the use and advocacy of the psychedelic drug LSD ("acid"). 

prototype

noun
  • An early sample or model built to test a concept or process. 

  • An original form or object which is a basis for other forms or objects (particularly manufactured items), or for its generalizations and models. 

  • A type of race car, a racing sports car not based on a production car. A 4-wheeled cockpit-seating car built especially for racing on sports car circuits, that does not use the silhouette related to a consumer road car. 

  • An instance of a category or a concept that combines its most representative attributes. 

  • A declaration of a function that specifies the name, return type, and parameters, but none of the body or actual code. 

verb
  • To create a prototype of. 

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