However, because of limitations or certain peculiarities of an engine, some designs or passive-background tasks may occur in a particular way for every game made using that engine. This particular feature (regardless of how central it may be to a game) is essentially the same in all games created with that engine, which takes it outside the scope of copyright. This reasoning would also apply to games made with the same engine which share source code—this would not constitute copying because the games' similarity is inherent to the tools.