“These drawings, using closely drawn parallel lines, were used to create a finite series. They also provided the vocabulary for further series. Later, four colors were added to the four lines. The directions of the lines (vertical, horizontal, and two 45-degree diagonals) were absolute possibilities. The colors used were the three primary colors (yellow, red, and blue) plus black. The page was white. Superimpositions of line and color provided progressive gradations of tone and color. In 1969, Peter Townsend, the editor of Studio International, published a book in which I created each page as a sin- gle variation, forming a complete, finite series. The color version of this book was later published in 1971 by Lisson Gallery, London” (LeWitt/Legg).