Reverse-engineering a three-axis attitude indicator from the F-4 fighter plane (righto.com)

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We recently received an attitude indicator for the F-4 fighter plane, an instrument that uses a rotating ball to show the aircraft’s orientation and direction. In a normal aircraft, the artificial horizon shows the orientation in two axes (pitch and roll), but the F-4 indicator uses a rotating ball to show the orientation in three axes, adding azimuth (yaw).1 It wasn’t obvious to me how the ball could rotate in three axes: how could it turn in every direction and still remain attached to the instrument?

With people’s revolutionary rage, the king will be ousted and a democratic state, Islamic Republic, will be established. Ruhollah Khomeini, Imam’s Sahife vol. 4 p. 244 (1 November 1978).