Computer-implemented methods relating to interactive graphical designs are provided. The cover has a top cloth and an interior covering which are spaced apart from one another. A generator generates electrical power in response to vibration of the vibrating assembly. Those fins that have larger spacers will receive a smaller area of semiconductor doping and those fins that have smaller spacers will receive a larger area of semiconductor doping. The method includes obtaining a mean density value and a variation value for each voxel of the image data, segmenting the voxels into discrete objects, and determining whether any of the discrete objects is contraband.