Grote vier - Big Four

"The big Four also dates from 1954, and here too larger versions of the work were later produced. The big four occupies a kind of middleground between the two groups of sculptures described above. It features not only the voluminous shapes of Four elements but also the peripheral composition of Airship, although the connectives the big Four are heavier and more centred. It is obvious from these examples that Visser was fascinated by the problem of the centre.
(Blotkamp, op.cit, p. 77)

See illustration