Modular surface treatment materials such as carpet tiles, ceramic floor and wall panels and tiles, ceiling tiles, vinyl flooring squares, wall covering materials, and the like, are provided in a matrix of a plurality of different colors and a sequential array of tonal variations within each color. A system and method, including a computer-aided design tool for laying out patterns of individual modular material units selected from the color-tone matrix, is included, as well as display devices for materials in the matrix.