Abstract: A computer system displays a first object that includes at least a first portion of the first object and a second portion of the first object and detects a first gaze input that meets first criteria, wherein the first criteria require that the first gaze input is directed to the first portion of the first object in order for the first criteria to be met. In response, the computer system displays a first control element that corresponds to a first operation associated with the first object, wherein the first control element was not displayed prior to detecting that the first gaze input met the first criteria, and detects a first user input directed to the first control element. In response to detecting the first user input directed to the first control element, the computer system performs the first operation with respect to the first object.

Abstract: An apparatus and process which can be used to determine the top dead center position of a piston. The apparatus includes an actuator plunger which engages the rocker lever of an engine cylinder, and a gauge indicator to measure movement in the rocker lever when it is engaged by the piston. The process includes measuring the position of the piston on the upswing of the power cycle and in a corresponding position on the downswing of the piston during the exhaust cycle. The center point between these two measurements is the top dead center point of the piston.