My idea is that a person as s/he moves around the mouse, moves around four mouse pointers simultaneously and thus moves the mouse around less and has it therefore easier and is therefore less receptive to RSI. The pointers move at the same time, in the same direction and at the same speed. Imagine four 'squares' dividing up the screen. And each pointer is centered as it is placed in the center of such a 'square'. Now which pointer is active? The latest direction of the pointers...

Pushing a button produces a tone/chord and subsequenly a piece of music. Let's use the sound of a piano as an example. So upon pressing the button('s) (say not more than two) the tones and/or chords of a piece of music are reproduced one by one and the volume of each individual note/chord is determined by the intensity of each press. So the piece or song has been written and recorded but the person pushing the button(s) determines how it is performed: the volume of each note/chord and the...