There are some nice visual markers as well that accompany the audible navigation which are very helpful and nicely implemented. (pixelatedgamer.com)
Since the early 1990s, Bag has been a pioneering figure in both video and performance art, often using the ubiquitous visual markers of television as a formal device. (teamgal.com)
These distances should be clearly marked in the video with visual markers such as cones, colored tape, or other items. (mydoghasclass.com)