My understanding is that before mouse pointer there was a light pen aka light gun pointer. It was used perpendicularly to the screen, literally pointing at the

My understanding is that before mouse pointer there was a light pen aka light gun pointer. It was used perpendicularly to the screen, literally pointing at the desired location. Then, when implementing a more 'remote' on-screen pointer, the notion of pointing perpendicularly at the site was best projected by a tilted 2D marker. Think of the mouse pointer kinda sticking out of the screen as a dart. I can't imagine the arm strain the users of the light pen had to endure back in time ... Though the workflow was probably still more keyboard-bound. https://en.m.wikipedia.org/wiki/Light_pen https://en.m.wikipedia.org/wiki/Light_pen