Acoustic holograms can be used to form complex distributions of pressure in 3D at MHz frequencies from simple inexpensive ultrasound
sources. The generation of such fields is vital to a diverse range of applications in physical acoustics. However, at present, the application of
acoustic holograms is severely hindered by the static nature of the resulting fields. In this work, it is shown that by intentionally reducing the
diffraction efficiency of each hologram, it is possible to create stackable acoustic holograms that can be repositioned to reconfigure the
combined acoustic field. An experimental test-case consisting of two holograms, each designed to generate a distinct distribution of acoustic
foci, is used to demonstrate the feasibility of this approach. Field scans taken for four different positions of the two holograms confirm that
the individual patterns for each hologram can be arbitrary translated relative to one another. This allows for the generation of a much greater
range of fields from a single transducer than could be created using a single hologram
