Glass has made many transformations since its inception. Ben Reid's June 28th, 2014 article, "Evolution Of Google Glass From Year 2010 To Present Day Explorer Edition," depicts the evolution process of Glass from the earliest to the most current version.
Now that Glass has launched, designers and staff members have been talking openly about the development process associated with Glass in order to give the world more of an understanding about one of their newest technology developments. In fact, Glass' main designer, Isabelle Olsson, did just this in a YouTube video:
After the most current version of Glass was created (the very last Glass device pictured below) Google was eager to introduce it to the public; however, Google knew Glass needed to be tested. So, instead of continuing to sequester Glass within the walls of Google, they announced Glass Explorer: a program through which interested consumers could apply to test, trial and use Glass in real-life situations.
Google Glass evolution process: The oldest version is featured first and the newest version is the last bottom-right device.