A telestrator is used for an electronic device that generates drawn video images over a background image.
The telestrator was invented by physicist Leonard Reiffel, who used it to draw illustrations on a series of science shows he did for public television in the late 1950s. The user interface for early telestrators required the user to draw on a TV screen with a light pen, whereas modern implementations are commonly controlled with a touch screen or tablet PC.
NFL color commentator John Madden famously used a Telestrator during football games for many years, boosting the device's popularity. His trademark frequent use of the device has been parodied on a number of occasions by comedian Frank Caliendo.
Former NBA head coach and current color commentator Mike Fratello was dubbed "The Czar of the Telestrator" by Marv Albert for his masterful way of diagramming basketball plays on screen, as well as his in-depth analysis and ability to break down offensive and defensive plays.
Howie Meeker, NHL hockey color commentator and studio analyst, used the telestrator for many years on CBC's Hockey Night in Canada and TSN to analyze plays during intermissions. He was famous for shouting instructions to "the boys in the truck" such as "Back it up! Back it up!" and "Stop it right there!" in his trademark squeaky voice.
Wrestling announcer Bobby Heenan briefly used this while in the then-World Wrestling Federation, calling it "The Brain Scan". He would usually use it during a post-match replay to doodle derogatory pictures or comments directed at the babyfaces in the called match.
Today telestrators are widely used in broadcasts of all major sports. They have also become a useful tool in televised weather reports. It is also used humorously on the show Wipeout, mostly by John Henson.