From Flying Saucers Uncensored by Riley Crabb, 1960.

From Modern Theatre Practice, A Handbook for Non-Professionals by Heffner, Selden & Sellman, 1935.

This is identified as a Venn diagram in Organisms, Teacher's Guide, 1996.

From Mercury, 1920.

From The Story of Mankind by Hendrik Willem Van Loon, 1923.  (So many inaccuracies in this book, but then again history books have always offered the most fiction.)

This Venn diagram, courtesy of literary scalawag and connoisseur of 60s movies Jonathan Caws-Elwitt, interprets an obsolete classification system once used to pigeonhole the bachelors of yore.

From Class-Book of Botany by Alphonso Wood, 1881.

This is the symbol left in the crib after the Lindbergh baby was famously taken away.  "There has been no genuinely convincing analytic work done on [this symbol] with respect to the Lindberg story" (Jerry Kroth, The Lindbergh Kidnapping, 2011).  [Note that the three black rectangles are actually holes that were punched in the paper and are not technically part of the design.]  The shaded object in the center is, of course, the "black egg" of alchemy, symbolizing the nigredo (a stage of putrefaction; the final step toward the "philosopher's stone" of enlightenment) and expressing "the precarious balance of the hermaphrodite, exalted by a [threatened] equilibrium" (Johannes Fabricius, Alchemy: The Medieval Alchemists and Their Royal Art, 1994).

From Prof. Oddfellow's sketchbook, the Venn overlap of a gingerbread man and a man.