It seems you're asking about a game called "Magic Pen." There isn't a widely known physics game with that name. Could you be thinking of a different game, perhaps one with a similar concept?

To help me understand, could you tell me more about:

* What kind of physics game are you looking for? (e.g., puzzle, platformer, action)

* What are some key features of the game? (e.g., drawing objects, manipulating gravity)

* Do you have any images or videos of the game?

Once I have more information, I can try to identify the game you're thinking of and provide the rules.