Otto Piene

Otto Piene (18 April 1928 – 17 July 2014) was a German artist.
In 1957, Piene and Heinz Mack founded the group ZERO. For the closing of the 1972 Summer Olympics in Munich, Piene created the sky work "Olympic Rainbow", made up of five differently colored helium-filled polythene tubes. 
Piene died in Berlin after presenting an art exhibit there. He was 86 years old.