Multiple independent images are presented on multiple display devices by driving the display devices with a common set of control signals and a multiplexed set of data signals that convey information representing interleaved components of each independent image. The first unitary measurement strip includes a first set of one or more windows, each window of the first set of one or more windows is configured to correspond to a first respective tangential location of the rotational component at the first axial location, and each window of the first set of one or more windows is configured to be detectable via a first sensor. Rotation of the at least one magnet of the external adjustment device effectuates rotational movement of the permanent magnet of the adjustable implant and alters the dimension of the adjustable implant.