Being a fan of the Matrix movie does not mean that you would like to see the characters of Matrix being shown on your computer screen. It is likely that you just like a symbol for Matrix so that you do not have to explain your computer's background to everyone who can possibly see them. The black background of this theme is the perfect backdrop for the codes that are in green that are placed all over the screen. The codes seem to follow a rhythm that may not be apparent to the naked eye but probably looking at it long enough will make you think differently. Of course, it is just a theme.