function rand ( n )
{
  return ( Math.floor ( Math.random ( ) * n + 1 ) );
}
var imgs1 = new Array("/images/acantilado-home.jpg","/images/ventanal.jpg","/images/ciudad-contacto.jpg","/images/teclado.jpg","/images/edificio-2.jpg","/images/desierto.jpg");

var imgCount = imgs1.length - 1;
var actual1 = -1;
var actual2 = -1;

function cycle2(id) {
	var current = rand(imgCount);
	
	if( id == "logoizq1" ) {
		actual1 = current;
		while( actual1 == actual2 ) {
			current = rand(imgCount);
			actual1 = current;
		}
	}
	else
	{
		actual2 = current;
		while( actual1 == actual2 ) {
			current = rand(imgCount);
			actual2 = current;
		}
	}
	var logo = document.getElementById(id);
	logo.style.background='url(' + imgs1[current] + ')';
	//alert(logo.background);
	current++;
}
window.setInterval("cycle2('logoizq1')",2000);
window.setInterval("cycle2('logoizq2')",2000);