function addSign(sign, size) {
  var code, codeleft = "", coderight = "", style = "", type;
  switch(sign) {
    case "lceil" :
    case "lfloor":
    case "lround":
    case "rfloor":
    case "rceil" :
    case "rround": type = "bracket"; break;
    case "rArr"  : type = "arrow"; break;
  }
  switch (type) {
    case "arrow":   codeleft = "<span style=font-size:14pt>";
                    coderight = "</span>";
                    code = "&" + sign + ";";
                    break;
    case "bracket": switch (size) {
                      case 2 : coderight = "2.gif width=8 height=32>"; break;
                      default: coderight = ".gif width=4 height=12>";
                    }
                    code = "<img src=http://www.d2wissen.de/font/" + sign;
                    break;
    default: return;
  }
  document.write(codeleft + code + coderight);
}