This is a Pomodoro timer indicator for your GTK panel.
sudo apt-get install python-gi
sudo -H pip3 install pomodoro-indicator
Start a timer with a stopwatch icon for 25 minutes:
gpi p 25
Start a timer with a coffee icon for 5 minutes:
gpi b 5
Icons files are obtained from http://www.pixeden.com/icon-fonts/stroke-7-icon-font-set. They are free for personal and commercial use.