title: Find the a 4 digit number whose square is 8 digits AND last 4 digits are the original number
body: <p>From the comments on <a href="https://stackoverflow.com/a/49659404/7607701">my answer here</a>, the question was asked (paraphrase):</p>
  <p><strong>Write a Python program to find a 4 digit whole number, that when multiplied to itself, you get an 8 digit whole number whose last 4 digits are equal to the original number.</strong></p>
  <p>I will post my answer, but am interested in a more <s>elegant solutions</s> concise but easily readable solution!  (Would someone new-ish to python be able to understand it?)</p>