https://www.corner-college.com/udb/cproVozeFxParagraphs_on_Conceptual_Art._Sol_leWitt.pdf.

Space can be thought of as the cubic area occupied by a three-dimensional volume. Any
volume would occupy space. It is air and cannot be seen. It is the interval between things that
can be measured. The intervals and measurements can be important to a work of art. If certain
distances are important they will be made obvious in the piece. If space is relatively
unimportant it can be regularized and made equal (things placed equal distances apart) to
mitigate any interest in interval. Regular space might also become a metric time element, a
kind of regular beat or pulse. When the interval is kept regular whatever is ireregular gains
more importance.