This is something I came across some time ago and I was super amazed by how cool-creepy the idea was and how beautiful-eerie turned out.
It's relatively simple: they took a set of cross-sectional photographs of the corpse of an executed prisoner (!!) -that came from an study for anatomy investigation purposes- and they animated them and played the video fullscreen on a portable monitor that was moved around resulting long-exposure images of the entire cadaver.
For more info, don't miss Project 1231 website.
And yes, the prisoner was executed at 12:31.