Abstract: A compound rotational interface and stepper assembly, the assembly including: a stepper supporting linear, rotational or both linear and rotational motion on a longitudinal axis; a compound rotational interface including a compound pinned parallelogram in a scissor arm arrangement bound by a first end coupled to a base and a second end coupled to a first rotational joint, the first rotational joint coupled to the stepper; the compound pinned parallelogram moveable from a first linear position to a second linear position and the first rotational joint moveable from a first angular position to a second angular position; and a linear direction defined by the compound pinned parallelogram substantially perpendicular to an axis of rotation defined by the first rotational joint.