Mosaic-like brick and mosaic-like surfaces made using such bricks

In discrete decorative bricks preformed for subsequent use in laying horizontal patio-brick surfaces, each such discrete brick having (a) a display face, (b) a preformed planar back face spaced a constant first dimension from the display face, such back face and first dimension being identical with the back faces and comparable dimensions of other such bricks, and (c) four preformed lateral abutment surfaces for abutment with the lateral abutment surfaces of other such bricks, each abutment surface being substantially uniplanar, orthogonal to and adjoining with two of the other lateral abutment surfaces of the brick the improvement wherein the discrete brick includes a network of interconnected grooves at least some of which have varying display-face widths along their lengths, the grooves extending from the display face toward the back face to depths that are at least twice the display-face widths, thereby to form a multiplicity of irregularly-shaped mosaic-bit surfaces on the display face to form a mosaic simulation thereon.