docs: function includeJscad(fn) {
  // include the requested script via MemFs if possible
    if (typeof(gMemFs) == 'object') {
      for (var i = 0; i < gMemFs.length; i++) {
        if (gMemFs[i].name == fn) {
          eval(gMemFs[i].source);
          return;
        }
      }
    }
  // include the requested script via importScripts
    var url = self.relpath+fn;
    if (fn.match(/^(https:|http:)/i)) {
      url = fn;
    }
    importScripts(url);
    return true;
  }