A chair designed for support is measured by how well it holds a body in place. A chair designed for variation is measured by something else entirely: how gently and how usefully it can change the body's configuration over time.
That reframing has concrete engineering consequences. Variation must be small enough to remain unobtrusive, slow enough to avoid disruption, and coordinated enough to keep the seat stable throughout. Those constraints define the design space BAID is working inside.
It also changes the evaluation criteria. Instead of asking only whether a seated position is comfortable, we ask how the distribution of muscular engagement changes as the seat inclination changes — which is where biomechanical simulation becomes useful.