In any case, this is how I went about it:
The two control strings for the head (1 and 4) allow it to not only turn left and right, but as I said before to tilt sideways and bow as well. In a traditional marionette these strings are played like an instrument, varying the tension, twisting and plucking.
When the marionette needs to kneel or jump etc. you are not really concerned with this since the entire body, head and all is balanced by your hand, which uses your own personal embedded experience as a subject of gravity to effect movements which prove extremely hard to program convincingly. Imagine for example that you want the character to tilt his head slightly in an inquisitive way while bowing and kneeling at the same time. If you try to break that into individual movements performed by individual muscles of your hand, fingers and arm you will picture the complexity of the apparent simplicity. Don't forget that I said tilt his head in an inquisitive way!
So, in my dream I must have followed some of the principles Pólya suggests to poor souls in distress, like for example:
- Look for a pattern
- Draw a picture
- Solve a simpler problem
- Use a model
- Work backward
- Use a formula
- Be ingenious
So I let the strings continue on to the other 'hand' which would pull or let go to let the gravity do its thing. The combination of these elements (including the most important, gravity) give you a very rich and expressive palette of head "language". This of course I cannot convey simply by pictures, but I will eventually post a video of the movements.
There was another problem, which because of its apparent simplicity tends to be forgotten until it is too late. Remember the analogy with a string instrument. So it is that you must tune the strings of your marionette to the perfect tension which allows precise control while at the same time giving gravity and inertia room to infuse the movement with the illusion of life.
Easier said than done. First of all the strings are very thin and usually waxed or Teflon coated to prevent fraying. That makes tying and untying knots practically impossible. Then consider the awkward and tight places where the strings are connected. Finally, size. Things that are very easy at a human scale become wickedly difficult in Lilliput.
Bowl of Sushi by Hiroshige (Edo Period)
My love of sushi came to the rescue. Chopsticks! the bamboo sticks have the right diameter, are pleasant to touch and sight (and taste) and its transversal structure provides the friction necessary to prevent the 80 lb. Teflon string from sliding. This was my prototype but although it stopped that string diameter from sliding, my preferred string is .006" Fireline, which is a braided bead thread very strong and resistant to abrasion (it is used to weave the smallest glass beads). This string just went through my tensioner like a water snake.
So I refined my prototype incorporating an opposing path that effectively holds it in place. And what is more important and the reason for this exercise, it is easy to adjust as needed, to tune the strings of the instrument.