With few exceptions, works of this kind, referred to by Donald Judd’s studio as “stacks,” were made in ten units. These works are installed so that the volume of each unit and that of each interval between them are equal, ideally spanning the full height of the wall.

Judd installed three stacks in the north room in the east building at the Block. The stack allowed for a number of combinations including a single metal on all sides, referred to as “solid”; those with plexiglass on the top and bottom; and those with metal on the top and bottom and plexiglass on the three facing sides, referred to as “wraparound,” of which this piece is an example. All units in a stack are uniform in their appearance. The dimensions of all three stacks at the Block make them “large” stacks, while the units in a “small” stack measure six by twenty-seven by twenty-four inches and can be installed on shorter walls.

Though Judd used blue lacquer for a number of pieces beginning in 1964, including for untitled, 1964, he did not use blue plexiglass until 1967.