Systems are everywhere. Have students prove with evidence that there are systems within and associated with writing. They can do the same with the other areas of study in school: math, science, history, computer science (coding, etc), music, physical education, and the like.
Have students prove with evidence that systems are all around us in our world and daily lives. Students were assigned homework on the first night to bring back evidence proving this premise. This image shows the board displaying student work.