// params: title, web, title, web, ...
static JTabbedPane showTabbedWebs(O... params) {
  O[] x = cloneObjectArray(params);
  for (int i = 1; i < l(x); i += 2) {
    CirclesAndLines cal = webToCAL((Web) x[i]);
    Canvas canvas = cal.makeCanvas()
    calAutoLayout(cal, x[i] = canvas);
  }
  ret showTabs(x);
}