This invention relates to novel composites comprising plastic and plant material derived from members of Partheuium spp. In one application a void space that is subsequently closed by actuated parts is initially filled with a material that is highly compressible and has voids that allow it to compress without undue resistance to part movement when the void volume is reduced. The port allows for adding or removing fluid from the expandable member in order to adjust the volume thereof and thus the interspinous process spacing. This invention removes the colour differential but does not remove any detail underlying the features of the image.