In accordance with certain embodiments, lighting systems include one or more lightsheets each including a plurality of strings of light-emitting elements, control elements, and power conductors for supplying power to the light-emitting elements and control elements. First and second scaling parameters P and Q are determined in accordance with the block numbers L and M and the scaling ratio LM or ML. The center member has opposing ends, and is axially split into at least two pieces. The insert is locked into the cutting head by the sleeve of an abrasive-carrying conduit, and provides the mixing region in which the abrasive is entrained into the waterjet. A fully supported surface is available through extension of an attractive upright chair.