I also got the chance to work with other design interns. We built a logo for one of the sister projects Jupyter works with, IPython. We had to carefully select the font and have a reason behind every pixel. Later in the summer, we made the hero graphic for our JupyterCon booth, as well as posters for a poster session at the convention. The 10ft hero image was so big that Illustrator couldn't render the the drop shadows properly, and we had to do some quick thinking to make sure we got the designs we wanted. I also got to help update jupyter.org as the convention got closer.
At the international convention for JupyterCon users, I participated in the poster session to talk about my work one-on-one, networked at Project Jupyter's booth, attended talks, and conducted user testing.
If you'd like to see the extensions in action, uses the following links and click the pink "launch binder" button in the ReadMe: