I made a Snake-like game with Unity this last Sunday and I pushed it to my github, then feel free to download the source code. If you prefer to copy the link, it’s here: https://github.com/joaokucera/unity-snake.
There is a live demo here to play.
There is no license, no condition, download and use it as you wish. I hope this helps you to study #unity3d and if this help you then give me a github’s star.