A pattern may be thought of being composed of fictious particles which exert attractive or repulsive forces at one another as charged particles do. Imagine two such particles. Let us assume that within a certain distance, they exert at each other an attractive force as a function of the distance and that at a distance farther they exert at each other a repulsive force. The force exerted on a particle is obtained by summing the forces from other particles. Then the displacement of the particle is determined proportionally to the force. The pattern is deformed as the particles move. The process is simulated in a digital computer and is repeated until the pattern becomes stationary being composed of several separate points, such as the end points, the cross points the bending points and so on. The stationary patterns for most of the OCR-B font alphanumerics are different from each other. This makes their discrimination quite easy.