A method and apparatus providing visual feedback to a computer user while dragging selected text is described. The circuit comprises the following components. The depth camera system may use cameras or projectors with different baseline distances to generate depth data. By using multiple absolute difference determinators, the throughput of the DSP is increased. The notches of the second set of stacked lamina are aligned with each other to define a passageway into the internal cavity with the bore of the post being aligned with the passageway to expose the bore. According to the invention, a sealing plate covering the attachment screws is installed removably in a plate housing delimited by a plate housing wall provided on the handling device and by a portion of the base housing wall.