Abstract: An apparatus and method for teaching golfers proper putting fundementals. The apparatus comprises a device which removably mounts over a putter head, projecting a laser beam on the plane perpendicular to the striking face of a putter just over the sweet spot. The apparatus also includes a means for the golfer to properly align the eyes vertically above the striking face. The laser beam is directed towards and on a linearly calibrated target strip. By directing a shot at various positions on the target strip while viewing the putter from a proper vertically aligned position, a golfer is able to learn to judge putting situations.

Abstract: A single object functions as a centralized monitoring point for events fired in a hierarchical object model. Objects within the hierarchy register with the event monitoring object when they are created. These objects then route their events to the event monitoring object. A listening object also registers with the event monitoring object to receive notification upon the occurrence of certain events within the hierarchy. A property of the event monitoring object corresponding to a particular class of object is parameterized with an identifier that designates the events to be sourced to the listening object The event monitoring object couples the listening object to a filter object that sources only events designated by the parameterized property. The event monitoring creates the filter objects as needed. A filter object can report events to more than one listening object if the listening objects register to be notified of the same events.