What is the instrument called that is constantly moving on the right of the screen at the back of the presenter. its on the tip of my tongue but i cant quite remember!! [[https://youtu.be/EnnUmnHR-s4?si=tecXyuGtJyeC73re https://youtu.be/EnnUmnHR-s4?si=tecXyuGtJyeC73re]] Thanks to anyone that knows and tells me!