While he began as a painter, later in life the third skin - the home, or architecture - greatly interested Hundertwasser. He hated the way most buildings had straight lines and angles. He felt that buildings should fit and represent those who lived inside them. His building designs use natural forms, and often fit around nature rather than trying to bend nature to fit them. In the Hundertwasserhaus, an apartment building in Vienna, Austria, the floors aren't flat and even: they undulate.