Methods and systems for applying material onto a work piece. Two electrodes are mounted on the base member’s front surface and each have an electrically-conductive contact surface. The rotator receives a rotate amount and an input operand with a size less than a maximum operand size supported by the processor. Accordingly, the position of the switching substrate andor fiberlens array may be adjusted until back reflected light having predetermined power is detected. The first computing device identifies a plurality of contextual items based on the first plurality of contextual keys and the second plurality of contextual keys, and presents a user interface depicting a plurality of contextual item references, wherein each contextual item reference corresponds to one of the plurality of contextual items.