Techniques for generating media keys for media data. The elastic connector is stitched on an inner portion of the sleeve and has a button opening that extends through a sleeve opening for attachment to a button on the sleeve. Methods for introducing a nucleic acid into a neuron are also described. The user enters the selected color into the printer, using for example a number or position code, or by marking the selected color on the print media, which is then re-scanned by the printer.