I tried installing GNOME packages to Ubuntu 14.04(unity). I used these codes.
sudo apt-get install gdm
sudo apt-get install gnome-shell
sudo apt-get install ubuntu-gnome-desktop
sudo add-apt-repository ppa:gnome3-team/gnome3-staging
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install gnome-weather gnome-music gnome-maps cheese gnome-documents
That did not do well, So i removed them completely using
sudo apt-get remove gdm
sudo apt-get remove gnome-shell
sudo apt-get remove ubuntu-gnome-desktop
And now i am not able to change my desktop wallpaper.A right click on desktop is not working. I think it removed the necessary packages of Unity also .Even the login screen display has not changed from GNOME style to Unity style. Is there a way to regain the original Ubuntu unity style?