You could perhaps create some sort of loop as @sebi210 suggested, and you could also increment it in an effect where a new part is created of the snow color that is slowly increasing in size(the part is). Then once the snow colored part fully takes over you could make the original part disappear. Depending on the size of the area you use this “effect” on it could cause issues within the game for users. Not sure if this would work on roblox, but there are definitely other algorithms that could work! If something is wrong with my method, or it isn’t valid then please feel free to correct me.