Marking version in Latex

Package prelim2e allows you to mark versions in Latex. The information will appear on the bottom of every page. It is quite simple to use it.
Add \usepackage{prelim2e} before \begin{document}. And then renew the version text as follows.

• \renewcommand{\PrelimText}{Draft}, where Draft is the text you want to insert. \PrelimText represents the whole thing as shown in the figure.
• Another way is \renewcommand{\PrelimWords}{Preliminary version: \textbf{\emph{draft}}} , if you want to keep the time information. Preliminary version: \textbf{\emph{draft}} is the text you want to change.

The figure above uses the following command:
\renewcommand{\PrelimWords}{\textbf{\emph{draft}}: ver. $\alpha \ 1.15$}

Please refer to the package document for greater detail.

Visual illusion

Before your eyes starts to deceive you, make sure you go along with the following steps:

1. Keep your eyes move along the movement of the flashing/moving pink dot.
2. Stare at the black cross in the middle, the moving dot behaves different from the 1st one.
3. Concentrate on the black cross for a while.

Now, click on the image and find out what will happen. It should be

1. The moving dot is pink.
2. The moving dot is green.
3. all the pink dots will disappear slowly, while the rotating green dot remains (the 3rd step is hard to do, because you have to keep you eyes on the black cross with 100% concentration, and fill your brain with nothing.).

There is NO green color used in the image at all. Your eyes cheat.

Reference: http://www.newscientist.com/blog/lastword/2007/10/eye-for-pink.html