Close connections sometimes exist between very different looking works. Untitled 1966, a horizontal wall piece with a mathematical sequence of bulbous rounded shapes, originated in the early wooden floor boxes with inset pipes or troughs. In one box, his efforts to open up the volume led him to cut sections out of the trough, leaving semi-circular divisions and a view through into the interior of the box. The discarded pieces of wood were then attached to a flat wooden block and made into a wall piece whose profile and divisions are similar to these metal wall progressions.
Having works fabricated made it possible for Judd to define his works with the utmost precision. Floor boxes are reduced to the simplest form, yet the beautiful materials and the quality of workmanship contribute to their sensuousness. Untitled 1969 is a simple box open on two sides, with an outer skin of anodised aluminium and an inner skin of purple Plexiglas. The highly reflective Plexiglas bounces light and colour around inside the box deceiving the eye and causing joints to disappear. Both materials reflect the surrounding light and architecture giving the box an illusory, intangible quality.