Semi-constrained ball and socket joints

Regarding semi-constrained artificial ball (head) and socket (cup) joints such as the hip or shoulder joint, which allow for certain numbers of degrees of rotation along three independent axes. For example, one embodiment creates at least two axes of rotation through a super-spherical space carved out of the inner surface of the cup, with a cup-cable connecting two points along the super-spherical space, and a perpendicular head-cable looping around the head and the cup-cable within the super-spherical space, and with the head-cable residing in a groove. Another embodiment creates two axes of rotation through a combination of a 1) swivel with lever and/or 2) cable attached to a circular track (with the knob or ring around cable facing inward or outward), both of which have the center of the head as the center of rotation. The third axis may be created by a horizontal swivel and by wiggle room.