title: What is meant by "dovetailing"?
body: <p>While reading the reviews for Stephen Wolfram's "A New Kind of Science" on Amazon, I came across the following statement:</p>
  
  <blockquote>
    <p>Every computer science (CS) student knows the dovetailer, a very simple 2 line program that systematically lists and executes all possible programs for a universal computer such as a Turing machine (TM).</p>
  </blockquote>
  
  <p>Can someone give a "simple 2 line program" which illustrates "dovetaling"?</p>