From 1962 Turnbull intensified his exploration of elementary sculptural forms. Avoiding allusion, he simplified his work's formal complexity and asserted the physical properties of the materials used, emphasising qualities of shape, length, weight and thickness. The severity of design which Turnbull evolved is seen in '5x1'. Unlike Caro, Turnbull insists that the form of the whole work should be comprehensible instantly and completely. '5x1' is one of several works in which this is achieved through repetition of a number of identical elements. As with 'Parallels', Turnbull emphasises the autonomy of each individual unit and permits their arrangement to be varied according to the character of the display space.