What artist and poet — a founding member of the Dada movement in Zürich in 1916 — referred to himself as “Hans” when he spoke in German and as “Jean” when he spoke in French?

What German-born American painter had his first one-man show at Harvard University while his paintings were being removed from German museums and destroyed as “degenerate art”?

Answers here~ https://schristywolfe.com/2015/09/16/september-16/