Chess Apps, Chess Rules Disabled

Can anyone point me to any chess apps for iphone or ipad that allow you to play with chess rules disabled, ie to allow illegal moves?

Why would you want to make illegal moves?

I had the same thought, but then a potential answer occurred to me. What if you wanted to replay and analyze a real game in which one or more illegal moves were made, but not discovered until after the game was over? Most chess software will not allow you to do that, because it won’t accept the illegal moves. You can always go into “setup mode” and set up the position after the illegal move (as long as it’s not an illegal position), but it’s annoying to have to do that.