To obtain a covering on a supporting structure that has a visual appearance that varies with the angle of light from a light source impinging on the covering, there are provided parquet blocks having reference edges and top surfaces with geometric forms in parallel relationship extending to a higher elevation than the block's adjacent surface portions and extending at angles relative to the reference edges that varies from that of other blocks. The parquet blocks in plan view may be of varying shapes such as rectangular, triangular, etc. while the geometric forms may be, for example, any one of parallel ridges, lands between parallel slots, rows of selected shapes in linearly spaced, linear alignment, etc. Indicia may be provided on the blocks together with a chart having markings facilitating selecting and adhering the blocks to the supporting structure to obtain the desired pattern.