Nodding and shaking of head are common means of indicating assent or demural.

People with their eyes closed, or with their head in a bag, or blind, or behind a sofa, or looking at something distracting, cannot see nodding or shaking of head.

Person has headpiece fitted, mounted with two bells, viz. a high pitched bell oriented mouth-forward with clapper constrained to swing in a horizontal plane, and low-pitched bell mounted vertically with clapper constrained to swing forward and backwards.

Henceforth, nodding will be accompanied by low pitched sounds, and shaking of head accompanied by high pitched sounds.
-- pocmloc, May 07 2017

//common means of indicating assent or demural//

Not completely common. I had a Bulgarian guy working for me once, and it took quite some time to get used to the fact that in Bulgaria a head-nod means "no", whilst a head-shake means "yes".

Also, we really need full three-axis sensing. For instance, there is the Indian head-wobble - tilting the head back and forth about an axis that runs roughly from the nose out through the back of the head.
-- MaxwellBuchanan, May 07 2017


Bulgarians can wear modified headsets with the bells oppositely oriented.
-- pocmloc, May 08 2017


Why would this be necessary? Doesn't the rattle tip you off? Or is that only me?
-- RayfordSteele, May 08 2017


I think high pitch for yes and low pitch for no would make more sense.
-- notexactly, May 09 2017



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