Returns the standard Off Appearance for a CheckBox

@returns {AcroFormXObject}
function OffPushDown(formObject) {
        var xobj = createFormXObject(formObject);
        var stream = [];
        stream.push("0.749023 g");
        stream.push("0 0 " + f2(AcroFormAppearance.internal.getWidth(formObject)) + " " + f2(AcroFormAppearance.internal.getHeight(formObject)) + " re");
        stream.push("f");
        xobj.stream = stream.join("\n");
        return xobj;
      }