1st & Ten is a computer system that augments televised coverage of American football by inserting graphical elements on the field of play as if they were physically present; the inserted element stays fixed within the coordinates of the playing field, and obeys the visual rules of foreground objects occluding background objects. Developed by Sportvision and PVI Virtual Media Services, it is best known for generating and displaying a yellow first down line over a live broadcast of a football gamemaking it easier for viewers to follow play on the field. The line is not physically present on the field, and is seen only by the television audience.