function invert()
{
  var linkCSS = document.getElementById("structureCSS");

  if( linkCSS.href.substr(-13) == "structure.css" )
    linkCSS.href = "/structureNeg.css";
  else
    linkCSS.href = "/structure.css";


  var images = $(".imageNeg");
  for( var i=0;  i<images.length; i++ )
  {
    var src = images[i].src;

    if( src.search("neg") > 0 )
      images[i].src = src.substring(0, src.length - 4);
    else
      images[i].src = src + ".neg";
  } 
}

function flicker()
{
  soundFX.sendEvent('PLAY');
  invert();
  setTimeout( "invert()", 250 );
  setTimeout( "invert()", 500 );
  setTimeout( "invert()", 750 );
}