var WID=31, HEI=31, pxWID=15;
var x = Math.floor(Math.random() * (WID - 1));
var y = Math.floor(Math.random() * HEI);
if ((x + y) % 2 == 1) x++;
var html = '<div><table cellspacing=0 cellpadding=0 border=0><tbody>\n';
var td = '<td width=' + pxWID + ' height=' + pxWID + ' bgcolor='

for(i = 0; i < HEI; i++) {
    html += "<tr>";
    for(j = 0; j < WID; j++) {
        var bg = (i + j) % 2 == 1 ? "white" : i != x || j != y ? "red" : "blue";
        html += td + bg + '></td>\n';
    }
    html += "</tr>";
}
document.writeln(html + "</tbody></table></div>");