Abstract: A surface covering unit comprises x primary elements, wherein x is an integer equal to or greater than 1. Each primary element is a rotational tessellation having a plural pairs of sides extending in a generally radial direction from plural vertices, respectively. In each pair, the two sides are rotationally spaced by an angle of 60, 90, 120 or 180 degrees, and each side is substantially a rotational image of the other side. The sum of the plural vertices angles is 180, 240, 270, 300 or 360 degrees. Preferably, all of the sides are irregularly shaped, but one or more sides could be wholly or partially straight. Optionally, one or more edges of each unit are marked with indicia to facilitate matching mating sides of adjacent units. A wide variety of units may be constructed having different numbers and arrangements of primary elements. As all the units are combinations of primary elements, they readily mate with each other.

Abstract: A garden edging system is made up of (a) one or more straight edger units, (b) one or more curved edger units and (c) one or more corner units. Each unit has a connecting face at each of its ends for connecting and holding adjacent units in end-to-end alignment with one another. The connecting faces facilitate the layout of a myriad of garden edging designs. The curved units have both their convex side and their concave side formed on the same arc of curvature so that a plurality of the units may be nested together with the concave side of each unit engaged flush against the convex side of the next adjacent unit. This facilitates packing and shipping of the units and mitigates against damage to the units. The units are dimensioned and sized to be stronger, more damage resistant, more versatile and more user-friendly than conventional edger bricks or tiles. A process of making the edger units is also disclosed.