Sorry I will add more information.
The circle object is not a part of gas cell and it's state won't be included in gas cell. They just interact with eachother.
The most important things I want to know are:
(Sorry I'm bad at communicating, I will add more information once I found it is needed)
I want to make a 2D game with gas (stardust) simulation. (I'm lazy to learn statistical physics and integrate thing by my self so) I want to know how gas spread, and how gas interact with circle object.
There will be 2D square grid. Each cell contains values of the state of the gas (a struct...