A telestrator is a device that allows its operator to draw a freehand sketch over a moving or still video image. The telestrator (or video marker) is most famously recognized in sports and weather broadcasts to diagram and analyze sports plays or incoming weather patterns. The user typically draws on a touchscreen with a finger or uses a pen on a graphics tablet. From the touchscreen or tablet, the drawing signal is communicated to the telestrator, which overlays the video image with the drawing and outputs the combined signal for broadcast or display.