var time = 0;
var metatime = 500;
var metadir = -2;
var color = false;

function uunnii(){
	time = Math.floor(Math.random()*metatime) + 5;
	metatime+=metadir;
	if(metatime<10||metatime>1000)
		metadir = -metadir;
	color^=true;
	document.body.style.backgroundColor = color ? "#000000" : "#ffffff";
	setTimeout("uunnii();",time);
}