A fuel injector assembly includes a modular fuel injector unit and a cylinder head side member. The first groove defines a first side surface and an opposite second side surface. The method: programs the lower page of predetermined memory cells with first predetermined data and the upper page with second predetermined data. An index generating unit assigns the index to at least one picture among the pictures which constitute the selected cluster. In addition, to add to the structural integrity of the constructed shoes, a part of the vamp or its strapping, may extend upwardly, and have a loop formed therein, or even loop back on itself, and which may embrace the upper part of the changeable vamp, to facilitate its retention, and structural configuration, when the vamp is turned, to vary its appearance. Thus, a function assigned to a physical key may easily be recognized by a user.