F for Font Awesome
Nice visuals are great way of keeping user's interest in online courses and as not every e-learning developer has super awesome designing skills, all the free graphic and icons come in handy in that case. There is a lot of free stuff on the internet to use in your private or commercial projects (always double check the End-user licence agreement to avoid any problems). Have a closer look at the simple picture above - in terms of designing, these icons are quite easy to draw b