In which country was the artist Mark Rothko born?

Latvia and Oregon both need a comma after them. Parenthetical commas, always two.

Painterly? How does a painterly rectangle differ from a geometric one?

Mark Rothko was thought to have committed suicide because of 3 things; 1) Struggles as an artist, 2) Breakup of marriage, and 3) Poor health

Cozzy 25, I wonder why he Suicided?

Cozzy 25, Never heard of him. Got it wrong! Lol