On the Writing of the Insane by G. Mackenzie Bacon, 1870.

"I am equal to the other two fellows," from School: A Monthly Record of Educational Thought and Progress, 1908.

From De Vulnere Cerebri Non Semper et Absolute Lethali by Daniel Sigmund Gottlieb Behrens, 1733.

An angel in the seventh heaven is said to have a rooster's shape (as per Romans de Mahon), but which is it — a rectangle or a triangle?  From A Little Journey Among Anconas by Cecil Sheppard, 1922.

Budding mathematicians, ironically, tend to blossom in winter months when plants are hibernating.  We learn this in Practical Physics, 1922.

You knew that everything is just a little bit better in Scandinavia, but here's why: How "No. 1" Became "1 1/2" in Norway by J. Maitland Stuart, 1891.  Now it becomes clear — when Norwegians "turn it up to eleven," it's a bigger deal.

Hey, let's take five and have these guys to do the math, eh?  "Appreciable only by mathematicians," from The Purchase of the North Pole by Jules Verne, 1891.

You do the math: "Two stockings and two shoes added together make a great many when one has the dawdles."  From St. Nicholas magazine, 1910.

We say that "apples and oranges" can't be expressed as a ratio, and that's because mathematics is citrus-based and prejudiced against apples.  Note that "tangerine" and "tangent" share the same Latin source, "tangere" ("touching"); "satsumas" and "summations" are derived from the Latin "summa" ("highest"); "lemons" and "lemniscates" both come from the ancient Greek island of Lemnos.  It's worth pondering ("ponder" has the same Latin root as the Ponderosa lemon ["weigh"]) just how Ugli the citrus bias is, my little Clementine.

1 + 1 = 3, for large values of 1.

The (seemingly improbable) fourth side of a triangle, identified in this comic panel from Punch (1871), wasn't officially measured until 1993 by the University of Adelaide's B. F. Sherman (Mathematics Magazine, Vol. 66, No. 5).

From Prof. Oddfellow's sketchbook (and dedicated to Hugh Thomas):

Beguiled by a Mystery

(Our guest blog for Gordon Meyer's Rebuilding a Mystery)

The question isn't whether the box is foreground or background; the question is one's own place within in the mystery (in which case, thinking inside the puzzle box may possibly be preferable!)  Optical illusions, phantasmic artwork, and even family snapshots ask us to consider our own beguilement, as it was, as it is, and as it will be.