Some things to take note of:<p>Scroll bars are on the left, and the scroll buttons are at the same end of the scroll bar.<p>NeXTSTEP GUI programs adhered to a well-defined concept of an <i>application</i>: they're stored on-disk as self-contained app bundles that appear in the file manager as a single file, there's one Dock tile per application, one menu per application, and zero or more windows per running application. OS X has somewhat weakened this.<p>Menus are vertically arranged, and can be re-positioned. Sub-menus can also be torn off and re-positioned.<p>Unlike OS X's Dock, when you fire up an application that isn't already in the Dock, the app icon goes in the bottom-left corner of the screen (which is also where minimized windows go). The app icons in the Dock are only the ones that you have selected to stay in the Dock even when the application isn't running.<p>The window close and minimize buttons are in different corners, and the close button provides visual indication of a window containing an unsaved document.<p>The display is grayscale, but the software supports color.