That’s what Hundertwasser said. He was an originally Viennese but ultimately globetrotting artist originally named Friedrich Stowasser, who ultimately renamed himself Friedenreich Hundertwasser (which is German for peacecountry hundredwater). You can see why he said that about the straight line when you look at his pictures, like Der Grosse Weg (which means the big road), from 1955:

or Hommage au Tachisme (1961):

or Regen auf Regentag (Rain on a Rainy Day), from 1972:

or Water Fire (1991):

He also designed buildings, often with plants, which he called “tree tenants”, growing out of them (another thing he said was “we must restore to nature territories which man has illegally occupied”). There are two of his buildings in the middle of Vienna. One is a block of flats, with a crowd of people who admire his work hanging around it (only the tenants are allowed inside):

The other is his museum, Art House Vienna, where I saw most of the pictures at the top of this post:

The last one is the gents toilet (where straight lines don’t naturally exist anyway…)