Back in 1998 when I was going through my GCSEs (high school) I took graphic design and two of my projects were: a phone, and a car.
My phone concept I believe (if it was valid), would be a good example of prior art for the iphone and other touch screen phones. It was a flat touch-screen phone, the exterior looked more iphone 4-5 & sg2, rather than the edges of the original iphone/3g, simply because we had to construct our phones and I was keen to keep it as simple as possible (other people were painstakingly carving individual keys).
Long story short I wrote up the project, explained the concept, designed it, carved it out of foam. I personally saw it as the evolution of the current technology, palm pilots were all the rage, phones were starting to get smaller, and I was addicted to my game boy. In fact I thought it was so simple that I decided to change tact for my final GCSE submission to do a car instead.
The car was and electric sports car, inspired by the Lotus Elise. Unless there is a patent for the concept of an electric sports car (which I doubt), I think there isn't much point going into this.
What I am most annoyed about is Apple and co, claiming 'design' innovation, where if my 12 year old self was able to come up with the same concept, it can't have been that innovative. Would a child's graphic design project count as prior art?