I see a video on youtube which display pomodoro clock in mode line
I installed lolownia/org-pomodoro: pomodoro technique for org-mode but it's clock does not show on the mode line
Alternatively, tried the answer How to show org-clock (and org-pomodoro) timer in mode-line? - Emacs Stack Exchange
Unfortunatley, it's wrong to report error when start emacs.
I found the the rainbow is nyan-mode: Nyan Cat for Emacs! which just display the scroll of the buffer.
How could I show a basic orgclock in mode line?