hand drawn piano roll player

You take a strip of paper and draw a melody on it in pencil (in pitch/time representation). Then you feed it through a slot containing a row of sensors that detect the resistance change due to the graphite, maps the position of the drawn parts onto pitches, and makes synthesized music as you feed it through.

It could be a box with a slot through which you feed a strip of paper. Or it could be a scanner that you slide across a piece of paper. Either one you can move forward, backward, or at different speeds, to create different versions of the melody. The scanner version you could also shift in the pitch dimension, to create transpositions of the melody.

Instead of graphite, it would be nice to sense color, or maybe different inks with distinct characteristic resistances, so you could make a composition for multiple instruments.

This could be fun to do for percussion too.

Update:

I just learned about the gloggomobil, which is a sort of mechanical rotary version of this idea- very inspiring and beautiful: