A shoe for the sticks canes and crutches having a base member with four outwardly extending pads and a central flat portion. The combustion chamber may be provided with an ignition system that allows for substantially simultaneous ignition of each of the plurality of the combustors. The method also displays to superpose a Z map attained from image signals reflecting the surface structure on a Z map attained from image signals reflecting the composition information with different colors, which makes it possible to clearly understand the spatial distribution of a substance of unique composition inside the sample. An XOR component receives blocks of plaintext data and blocks of ciphertext data, and XORs blocks of plaintext data for respective plaintext packets with previously encrypted blocks of ciphertext data for those plaintext packets. Thus, a large number of abrasive tools will have very similar operating characteristics, and abrasive tools made at different times or through different methods also can have very similar operating characteristics. In one implementation, a VCO is implemented with drain extended MOS transistors.