Hello Linux Geeksters.
In this article I will show you how to remove the dots from the Ubuntu 13.04 Raring Ringtail lightdm login screen.
Actually, it is very simple. All you have to do is this:
$ sudo xhost +SI:localuser:lightdm
$ sudo su lightdm -s /bin/bash
$ gsettings set com.canonical.unity-greeter draw-grid false