brushstroke: a mark left on a surface by the movement of a brush.
Nos quadros deles dá pra se notar como as pinceladas são fortes, deixando suas marcas pelo pincel que esconsta, desliza na tela. Sobre o quote dele achei no Yahoo alguém que publicou:
It means objects need a foil (to prevent someone from doing something they're trying to do), or contrast to show their true nature, even colors, need their opposites to shine. It is like how a jeweler puts diamonds on a black cloth to make them stand out. Yellows and oranges make blues shine truer. (like fruits,there is a huge variety of fruits, but let's suppose that there's only an apple as a fruit. Without other fruits we would never be able to try them and say "Oh, apple tastes better" or even "I prefer a pear better than an apple", although the contrast between things, that's what make we see their qualities)