History of painting group's theories. Next to van Doesburg, the group's principal members were the painters Piet Mondrian, Vilmos Huszár, and Bart van der Leck, and the architects Gerrit Rietveld, Robert van 't Hoff, and J. J. P. Oud. The artistic philosophy that formed a basis for the group's work is known as "neoplasticism" — the new plastic art (or "Nieuwe Beelding" in Dutch). Proponents of De Stijl sought to express a new utopian ideal of spiritual harmony and order. They advocated pure abstraction and universality by a reduction to the essentials of form and colour; they simplified visual compositions to the vertical
Pieter Voltelyn Graham van der Byl a very popular and respected figure by both opposition and government. In parliament, a National Party politician asked the speaker of the house if they could refer to van der Byl as "Oom Piet" (which is an Afrikaans term of respect, meaning "uncle Piet"), this was duly granted and van der Byl was henceforth known as "Oom Piet" in parliament and in the media. During his years in opposition, van der Byl's views on National Party government policy never changed, he vehemently continued to openly criticise the Apartheid regime for its extreme suppression of the non-white population and its transformation