title: Regular expression for strings with an even number of zeroes and ones
body: <p>What is a regular expression for strings of 0 and 1 with an even number of zeros and an even number of ones?</p>
  
  <p>I have something like <code>(1*01*01*)*(0*10*10*)*</code>.</p>
  
  <p>Does it look good?</p>