I am assuming this is achieved through a long exposure, but these artists are making live-action, moving light art. Having an epileptic seizure has never been so fun! If you cannot view the moving gif (maybe via your e-mail) then you need to pull the image into a browser window.
Link: http://tochka.jp/pikapika/2006/06/report_pikapika_in_kitijoji.html
CG
