Hello, I am new to iOS development. I have plenty of experience with C/C++ and Java programming, and am currently learning as much as I can about Cocoa Touch/Objective C. I would like to ask how deep in the Operating System one can go when programming for iDevices? Is it possible to change things outside of your app? For example, could I possibly change the app icon for a different app using my app? I am attempting to determine the viability of an app that could change the color mapping of the entire display while my app is running in the background. Thank you for any help you can provide.