Here's how you can install the Square-Beam icons in Ubuntu 14.04. You can use these icons with light or dark themes.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each.
sudo add-apt-repository ppa:noobslab/icons
sudo apt-get update
sudo apt-get install square-beam-icons
According to Noobs Lab:
This icon theme is elegant offers wide variety of icons, which contains more than 30,000 different icons. You can use Unity Tweak Tool, Gnome-tweak-tool or Ubuntu-Tweak to change themes/icons.More at Noobs Lab
Additional Ubuntu resources