title: Conditional formatting for cells when cell above has the same value
body: <p>Is it possible to apply conditional formatting to a whole sheet such that whenever the cell <strong>above</strong> the current cell has the same value (either text or number) as the current cell, the current cell will be formatted yellow fill/blue font?</p>
  
  <p>For example, when cell:  </p>
  
  <p>A1 is <em>blank</em><br>
  A2 AAA<br>
  A3 <strong>AAA</strong><br>
  A4 <strong>AAA</strong><br>
  A5 is <em>blank</em><br>
  A6 AAA<br>
  A7 <strong>AAA</strong>  </p>
  
  <p>only cells A3, A4 and A7 will be formatted with yellow fill and font blue.</p>