My project is a painting of New York City that lights up using lily-pad arduino. I learned how to program arduino boards for the first time. I had to use ten LED lights, and tons of sewing.
I can't remember the concepts I used other than coding. Practically everything in the real world needs light and I learned  how to program it. I used sewing and programming. I want others to notice the lights and how nice they look. I would add stars to my project. Yes, I re-did it twice to make it better.