Gesture and handwriting recognition agents provide possible interpretations of electronic ink. An emulator module connected to the self-checkout core application module emulates, independent from the self-checkout core application, a native vendor software application in a network of cashier-operated checkout terminals administered by a vendor server computer, the emulator module passing commands and data to, and receiving commands and data from, the vendor server. This attachment may be perforated for easy removal of the utensil bag. Then, selectively forming a SiGe optical path overlying the Si normal feature includes forming a SiGe vertical optical path overlying the normal feature walls.