A camming coupler for removably attaching a music desk or other object to an upright support leg. The composition is capable of inhibiting unwanted heat loss from production tubing or uncontrolled heat transfer to outer annuli. The source can be formed into a variety of different shapes such as points, cylinders, rings, squares, sheets and anthropomorphic shapes. Given a set of input events, test functions associated with nodes determine the path taken during traversal of the graph. Therefore, a surface discharge mode can be used even when applying negative pulses to the sustain electrode in a reset period, and a size and cost of a plasma display apparatus can be reduced by applying a negative pulse of the same magnitude as a sustain voltage without a separate negative voltage source. An alternative embodiment includes a method for matching objects by defining a plurality of bins for multi-resolution histograms having various levels and a plurality of cluster groups, each group having a center, for each point of interest, calculating a bin index, a bin count and a maximal distance to the bin center and providing a path vector indicative of the bins chosen at each level.