A method and apparatus for forming patterns in a flat, plastic material, such as, for example sheet vinyl, linoleum, and other flat sheet floor covering. Therefore, it recomposes, re-encodes and re-decodes the voltage signals output or input by a five-wire or a six-wire touch screen so as to make the processed voltage signals compatible with the four-wire controller for processing. Since no ground pattern is present on the amplification circuit, the ground node of the amplification circuit serves as a means for supplying a true ground potential.