The Elrod was a machine used to cast rules and spacing material (leading) of a specific width: 1, , 2, 3, 4, 6, 12, 18, 24, 30, or 36 point. This was used extensively in page layout and line spacing, that is, adjusting the white space between paragraphs and any other area when small bits of white space were needed. Large areas of white space were created by wooden or later metal blocks called 'furniture'. Smaller odd areas were filled with square or rectangular blocks in various point sizes called quads.