Irregular tessellated building units

1. A surface covering unit for use in combination with other ones of the of the surface covering units to form a surface covering comprising

at least one face comprised of at least one primary rotational tessellation element, the rotational tessellation element including

at least two pairs of sides, the sides in each pair of sides having the same length and being images of one another,

wherein the sides of one said pair of sides extend from a first vertex and are rotationally spaced from each other, and the sides of a second said pair of sides extend from a second vertex and are rotationally spaced from each other, the first and second vertices being spaced from each other;

wherein the sides of said first and second pairs of sides comprise two or more segments, at least one segment being a straight line;

wherein all pairs of sides have different lengths, and one pair of sides has a substantially different length than the other pair of sides; and

wherein said unit has an irregular configuration, and the surface covering has a natural custom-fitted appearance such that a repeating pattern is not readily apparent.

2. A surface covering unit as in claim 1 , wherein the face of the unit has a molded surface irregularity or variation therein.

3. A surface covering unit as in claim 1 wherein the sides of the first and second pairs of sides are two or more straight line segments.

4. A surface covering unit as in claim 1 wherein the first pair of sides are rotationally spaced from each other by a first angle and the second pair of sides are spaced from each other by a second angle, the first angle being different than the second angle.

5. A surface covering unit as in claim 1 wherein the first pair of sides are rotationally spaced from each other by a first angle and the second pair of sides are rotationally spaced from each other by a second angle, the first angle being the same as the second angle.

6. A surface covering unit as in claim 1 , further comprising a third pair of said sides that extend from a third vertex and are rotationally spaced from each other, the third vertex being spaced from the first and second vertices.

7. A surface covering unit as in claim 6 , wherein said third pair of sides are not straight lines or smooth curves.

8. A surface covering as in claim 6 , wherein all of said sides are two or more straight line segments.

9. A surface covering as in claim 6 , wherein each pair of sides has a different length or configuration.

10. A surface covering unit for use in combination with other ones of the of the surface covering units to form a surface covering comprising

at least one face comprised of at least one primary rotational tessellation element, the rotational tessellation element including

three pairs of sides, the sides in each pair of sides having the same length and being images of one another,

wherein the sides of one said pair of sides extend from a first vertex and are rotationally spaced from each other, the sides of a second said pair of sides extend from a second vertex and are rotationally spaced from each other, and the sides of a third said pair of sides extend from a third vertex and are rotationally spaced from each other, the first and second vertices being spaced from each other;

wherein all of the sides of at least two pairs of sides are comprised of two or more straight line segments;

wherein said three pairs of sides have different lengths or configurations, and one pair of sides has a substantially different length than the other pairs of sides;

wherein the unit has an irregular configuration and the surface covering has a natural custom-fitted appearance such that a repeating pattern is not readily apparent; and

wherein the face of unit has a molded surface irregularity or variation therein.