Our eyes perceive the world in two dimensions, sometimes referred to as x (horizontal) and y (vertical) components. Beyond that, since humans have two eyes, we can also perceive a third dimension corresponding to how far away something is. Cameras, however, resolve all of this into the x/y plane, taking a snapshot of an instant in time.
On the other hand, it doesn’t have to be an instant in time. Long exposure photography captures what’s going on in an area over several seconds or minutes, resolving the three dimensions we normally think about, plus a fourth, time, into a single 2D plane. This can produce some weird and amazing images, but what if you were to instead take an image displaying not the x/y plane, but a plane formed from x or y and time as the axes?
Hacker Jon Bumstead has done just this, creating a Raspberry Pi-based camera that draws images with one of these axes replaced by a time component. The concept is quite difficult to get your head around, but his Instructables explanation, along with the animated GIF of the process can shed some light on the process after some study.
But feel free to simply enjoy the video below using this time/x/y process, which is unlike anything I’ve ever seen:
In addition to showing how he built a portable setup for this technique using a Raspberry Pi, he even outlines how to implement this technique with normal video after the fact in step 14 of the writeup. This post-processing technique allows for more computational time, and is how the video above was produced.