must be east to west, no?

Depends on whether you're an Anglican or a Catholic.

In football and basketball, ball carriers use what is known as a "head fake". They look in one direction, and dart in the other, throwing the defender off balance momentarily.

I guess a head motion signaling dissent would be an "east and west head shake", represented graphically thus:

<0> or <0><0> or <0><0><0> depending on the degree of disagreement.