The entire code is published as free software, under a GPL v3 licence.
The user registration application was made with PHP and MySQL. The code can be downloaded here.
The drawing application embedded in this Web page is Chibipaint. The source code for Chibipaint can be downloaded from its Web site.
To project images onto the square, we have developed a programme in C++ using the openFramweworks library. To synchronize various computers carrying out the projection, we have used OSC messages. Our application code is available here --FIXME--.
For more information, go to the Web site of openFrameworks.
The other applications for joining various components were developed in PHP and Python, and you can get the code here --FIXME--.