In 1878, Eadweard Muybridge studied animal locomotion and took a series of pictures of a trotting horse to see every phase in a stride. How? He placed 24 cameras around a racetrack, each 27 inches apart. As the horse trotted past, a tripwire each shutter was snapped. Combined, those pictures became a precursor to motion pictures, and technically, the first GIF. In honor of this, Tobias Munzert has built a mechanical LEGO version that gallops in stride with the original animation.
The mechanics are timed really well to get that genuine look of a horse in motion. If you look closely, you can see that even the head pushes forward slightly. You should also take a closer look at the excellent parts usage on the neck, head, and feet!