The XScreenSaver application is a large collection of historic and educational graphics demos. XScreenSaver is the standard screen saver collection shipped on most Linux and Unix systems. I released the first version in 1992. In 2006, I ported it to MacOS, and in 2012 I ported it to iOS. This application is not a screen saver, of course, since iOS doesn't have those. But it does let you play with the hundreds of graphics demos that are a part of the XScreenSaver collection.