I need with figuring out a science fair idea! 
Judging from you being here, you want an idea of what to do with this (please correct me if I’m wrong)
You can build any kind of thing, whether it be addition, subtraction, multiplication or division, as long as it works, people will be impressed. Maybe explain what a Turing Machine is, and how this is Turing Complete, making it the most basic form of a computer. Tell people about Binary as well possibly, and how electronics use it. I hope your science fair project goes well!
Okay, thanks! I’ll think about it!