title: how to use a function created in a scene in other scenes as well in corona sdk?
body: <p>I have no experience in Corona SDK, please help.</p>
  
  <p>I have made a score function in a scene that when selecting the correct answer a <code>+1</code> is added and <code>-1</code> for wrong answer.</p>
  
  <p><strong>Q:</strong>
  How can I use\call this function in the other scenes that I have created without restarting the score?</p>
  
  <pre><code>-------------------score------------------------
  local score = 0
  
  local scoreTxt = display.newText("0", 0, 0, "Helvetica", 40)
  scoreTxt:setReferencePoint(display.TopLeftReferencePoint)
  scoreTxt.x = display.screenOriginX + 700
  scoreTxt.y = display.screenOriginY + 37
  scoreTxt:setTextColor(2, 2, 2)
  ------------------------------------------------------
  ---------------------score added 10-----------------------------
  
  function updateScore()
      score = score + 1
      scoreTxt.text = string.format(" %d", score)
  end
  
  local scoretimer = timer.performWithDelay(1, updateScore, 1)
  ---------------------------------------
  ---------------------score minus 1-----------------------------
  
  function minusScore()
      score = score - 1
      scoreTxt.text = string.format(" %d", score)
  end
  
  local scoretimer = timer.performWithDelay(1, minusScore, 1)
  </code></pre>