During the second half of the 20th century the artists followed the basic principals of the mordern art of before World War I.
The difference is that after the first world war the artists were very emancipated. In stead of working in groups, many artists developed an individual style, sometimes combined with existing or older trends
From 1960 on, the art movements were replacing each other more and more quickly. In 1980 one can count over 40 different art movements, existing closely together.
The artists did not bound themselves to one movement anymore. They represented themselves in more than one movement.