A plane with 4 sides.
Are you square? Do you live on a square? Do you walk or gather on the town square?
There is more information and inspiration on the Creative Prompt Page, which I have been updating fairly frequently.
Post the specific URL or deep link where your drawing, doodle, artwork is posted in the comments area of this post. It is an easy and good way to keep all the artwork together.
See the Creative Prompt page if you want to more information how to participate in this project. You can also click ‘Creative Prompt’ in the tag cloud and see more prompts and responses.