Emerald is a window border manager to beautify window borders in Ubuntu desktop. Following is a terminal window with Glassified MacOS border theme.

If you want to decorate your window border, you can try following installation and setup.

Step 1 : Install Emerald Theme Manager. It is available in official repository, just run this command in Applications -> Accessories -> Terminal:

sudo apt-get install emerald

Then Emerald can be launched from System -> Preferences menu.

Step 2 : Configure Compiz to enable Emerald. Go to System -> Preferences -> CompizConfig Settings Manager, search “Window Decoration” and click to go into its configuration window. Replace previous value in command box with emerald --replace

Step 3 : Download emerald border themes you like, then install them by import button in System -> Preferences -> Emerald Theme Manager