As specified above, a "dimension" is nothing more than a set of values representing a given direction within a system, and a multi-dimensional space can itself be thought of as a multiplication of several "copies" of these sets. For instance, the 3-dimensional space in which we live is often visualized as the set of all 3-tuples of real numbers (Thus, taking its values from the real number line, R), and is thus the result of the iterated multiplication: R x R x R = R³, likewise, 4-dimensional space is the set of all 4-tuples of real numbers, and is thus equal to R x R x R x R = R⁴, and so on and so forth.