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	function set_img(img) {
		var text = ""
		var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

		for( var i=0; i < 20; i++ )
			text += possible.charAt(Math.floor(Math.random() * possible.length))

		img.setAttribute("src", "https://sigil.cupcake.io/" + text + "?w=" + img_size)

		setTimeout(function(){set_img(img)}, Math.random() * 800 + 200);
	}
	function init() {
		img_size = 96
		var cx = (screen.width / img_size) >> 0
		var cy = (screen.height / img_size) >> 0

		for(var y = 0; y < cy; y++)
		{
			var tr = document.createElement('tr')
			for(var x = 0; x < cx; x++)
			{
				var td = document.createElement('td')

				var img = document.createElement('img')
				set_img(img)
				img.setAttribute("width", img_size)
				img.setAttribute("height", img_size)
				td.appendChild(img)

				tr.appendChild(td);
			}
			document.getElementById('t').appendChild(tr);
		}
	}

<body onload="init()" style="margin:0;background:#e0e0e0;">
<table id="t" cellspacing=0 cellpadding=0 />
</body>