You can rotate your primary Mac screen, including the built in screens on a MacBook Pro or iMac, by accessing a hidden pull-down menu within the Display preferences.
Here’s how to access the screen rotation option in Mac OS X:
* Launch System Preferences
* Hold down the Command+Option keys and click on the “Display” icon
* On the right side of the Display preferences, look for the newly visible ‘Rotation’ drop down menu
* Set the rotation you want, 180° flips the screen vertically
* Close Display preferences to have the settings stay
If you flip the screen vertically, you’ll notice that the mouse is flipped as well, this is pretty confusing at first and it definitely makes for a good prank to play on someone. Of course the real reason to rotate the Mac screen is to accommodate for different display setups, although rotating the internal display is a bit of an oddity which is likely why the setting to do so is hidden by default.
If you have an external display attached to your Mac, you’ve likely noticed that you can adjust the screen orientation on the external display by using the Display System Preference.