I have an slight idea of what you mean by seperating game mechanics and graphics but I would really apreciate it if you could tell me more
This Forum post about the FuzeCreek game should help clarify what I mean:
To dig deeper, you could peruse the source code, or you could clone the repo and run each version from source:
Although each version of the game has very different visuals, the “state” of the game is represented in exactly the same way.
The anti-pattern would be to store that state in the scene graph. For instance, a naive developer might store the number of remaining patches in the userdata of the Spatial that visualizes the raft. The code to move the raft forward might be in a custom Control added that that Spatial.