I’ve yet to see a running mirror, so I drew one. I think they’d use a double suspension gait of a sighthound (or a cheetah, maybe). Here’s a muave/sugar/shadow Shadow mirror with a sort of muted clown and peregrine (by osiemfr)—no name.
These animated gifs were generated from stereograms taken by John Hillers during the Powell Surveys of the Colorado River and the Grand Canyon in the 1870s. They are among some of the earliest photographs taken of the Grand Canyon.