You are a green snake. Use the arrow keys to try and collect the apples. If you hit the edge you're out. Good luck! (If there's an apple that's half outside the border, half inside, don't worry, its not impossible!)
I got the idea from a google easter egg. If you search up "Snake", a game will show up were a snake has to eat red apples to grow bigger and earn points. If it touches the edge, it's game over.