An interesting orchestrion used by the Swedish band "Wintergaten".
The first video shows the machine playing, then two detailed videos
on how it works.

  https://www.youtube.com/watch?v=IvUU8joBb1Q
 
  https://youtu.be/uog48viZUbM
 
  https://youtu.be/p0Guq7vZb_E
 

A link I got from the video is for an interesting gear program which
will generate a printable gear pattern.  You glue it to plywood and
cut out your own gears: http://woodgears.ca/gear/index.html 

Phil Jamison