Conversation so far:
When did Le Corbusier start painting?
1918
What did Le Corbusier do between 1918-1922?
Le Corbusier did nothing but concentrate on Purist theory and painting.
What is the name of Le Corbusiers cousin?
Pierre Jeanneret

Question: what kind of architectures did they design?
Self-contained rewrite: What kind of architectures did Pierre Jeanneret and Le Corbusier design?