DIY Animated Graphic Scores

I have recently been looking for simple ways of allowing people to control certain parameters of animated graphic scores using projections and surfaces suitable for drawing on, like interactive whiteboards.
The idea is that the score is presented with empty spaces which can be filled in at the start up screen of the video before the play button is pressed. When the video is played an animated action line indicates when the static sections, which were filled in, are to be played.
These 'fill in' scores will feature in the last chapter of the DabbledooMusic book for young musicians (coming soon)