In the last panel of the 14 July 1940 comic strip. Krazy Kat, the question is posed, "But is it square?"
1939 Krazy & Ignatz by George Herriman "A brick stuffed with moom-bims". Series editor Bill Blackbeard Seattle : Fantagraphics Books, 2007. ISBN13 : 978-1-56097-789-6. p. 93.