Seat with 3D motion interface

A seating system comprising, in combination:

• a left seat,
• a right seat,
• a base,
• a first elongate flexible support member having first and second longitudinal ends, the first flexible support member moveably connected to the left seat by a first joint at or adjacent to the first longitudinal end and to the base by a second joint at or adjacent to the second longitudinal end, and
• a second elongate flexible support member having third and fourth longitudinal ends, the second flexible support member moveably connected to the right seat by a third joint at or adjacent to the third longitudinal end and to the base by a fourth joint at or adjacent to the fourth longitudinal end,
• wherein:
• surfaces of the left and right seats are adapted to be simultaneously sat upon by a single human, all of these surfaces together defining an entire seating surface of the seating system,
• the entire seating surface may translate, without changing the displacement or orientation of any of the surfaces of the entire seating surface relative to each other, except displacement along the long axes of the first and second flexible support members, in a translation that is relative to the base, includes a lateral direction and—a vertical direction, and occurs solely as a result of internal movement of one or more of the first, second, third and fourth joints and the first and second flexible support members,
• the term “internal movement” meaning, with respect to a specified joint, movement of at least one part of the specified joint relative to at least one other part of the specified joint, which movement comprises rotation about an axis that intersects the specified joint, and the term “internal movement” meaning, with respect to a specified flexible support member, flexing of the specified flexible support member,
• a “lateral” direction meaning a direction that is parallel to a straight line segment that intersects the second joint and the fourth joint, and
• a “vertical” direction and a “front/back” direction each being defined by a frame of reference that
• is fixed relative to the seating system as a whole, and
• has three axes, being vertical, lateral and front/back, respectively, the lateral axis being in a lateral direction, which three axes:
• are perpendicular to each other, and
• are oriented so that, when the lateral axis is horizontal from an external observer's point of view, the vertical axis is vertical from the external observer's point of view, the external observer's point of view being oriented so that up and down are along the direction of maximum gravitational force being exerted on the seating system.