Take some verses for a spin

I knew what it was, but I didn't know what it was called. That's what I thought as I entered the elegant exhibition at the Grolier Club in New York. These magic movable circles, like some I'd played with as a child, are called "volvelles." The word is not in my 2,000-page desk dictionary. The sound is right, though. Volvelle - it feels like going around and around. (It's from the Latin,volvere, "to turn.") But it goes around with a purpose. One printed circle slides over another to expose answers to questions or to math problems.

It's a way to teach phonetics, put a 100-year calendar in the palm of your hand, or even inspire a CD-cover design (jazz guitarist Pat Metheny's "Imaginary Day").

As you circulate among the circles, the exhibition lives up to its title: "Volvelles: The Magnificent Art of Circular Charting."

Here are more than 120 volvelles, old and new, many on display for the first time. Could I make one? It should be easy to put together three wheels of words rotating on a spindle to give different combinations as they turn. But wait:

"There are volvelles that arrange their data peripherally, centrifugally, and radially," writes Jessica Helfand in "Reinventing the Wheel" (Princeton Architectural Press, 2002), which is all about volvelles. She put together this exhibition with William Drenttel. Some volvelles use circles and pointers. Some use lots of cutouts. Look on the facing page to see four volvelles - now often called "wheel charts" or "wheel graphs" - from her book.

Picasso and another artist, Dadaist Tristan Tzara, worked together on a "perpetual" poem in volvelleland. Maybe I could try something in the spirit of Dada, a word that is in my desk dictionary. "Dada" is an early 20th-century artistic movement of works "marked by nonsense, travesty, and incongruity."

April is National Poetry Month. What could be more fitting than to celebrate it with a haiku volvelle? Haiku? Yes, because The Home Forum has a tradition of haiku, and this Japanese form of verse has a symmetry perfect as a circle. A haiku consists of 17 syllables in unrhymed lines of five, seven, and five syllables. Traditionally, haikus tend toward the natural world. As in:

Staring in the lake
I saw a school of minnows
laughing up at me

But for our present purposes, how about:

Show me a volvelle
and I'll show you a circle
that tells a story

(Count the syllables. Did I get it right?) Note that the volvelle haikus have interchangeable parts that make sense or nonsense but never "no sense" as you turn the wheels. You can add your own haiku in the spaces provided so it can be interchanged, too. Or use this as a pattern to make a volvelle from scratch. For this month only, you can download and print out a free copy of this volvelle template at: www.csmonitor.com/kidspace.

A brief history of volvelles

They've been used for centuries to measure, record, predict, and calculate everything from star locations, to military history, to what to make with the food in your fridge. The earliest one dates back to 1306. It was an astrological table in a book written by a Spanish scholar named Raymond Lulli. The table had two movable pieces of parchment attached through their centers with thread.

Almost two centuries later, in 1540, a German mathematician and astronomer named Peter Apian published a scholarly work titled "Astronomicum Caesareum" ("Astronomy of the Caesars"). It was a lavish book with 36 hand-colored woodcuts, 21 of which included volvelles for computing planetary positions. Some had six rotatable dials. Tiny pearls on silk threads served as sliding indicators on some of the circular charts. Revolving paper wheels were well represented in astronomy books through the Renaissance. (Indeed, volvelles that show the positions of the stars at various times of the year are still popular today.)

Volvelles (often called "wheel charts") were especially popular in America from the 1930s to 1950s. They were used as educational guides in schools, tourist giveaways in gas stations, even as prizes advertised on the back of cereal boxes that you could send away for. A 120-volvelle exhibition at the Grolier Club in New York, titled "Volvelles: The Magnificent Art of Circular Charting," is on view through April 24.

- By Owen Thomas

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