'Tis the season for snowstorms and for the holiday-themed artwork that references them. Snowflakes abound these days, even in places not buried in last weekend's East Coast blizzard—in advertisements, on Christmas cards, on paper cutouts made by schoolchildren.

But at least one scientist has a gripe: many of those so-called snowflakes bear little resemblance to the real thing. Specifically, these stylized flakes often have four, five or eight corners, whereas the real things have six, a structural trait that arises from water's crystallization into a hexagonal lattice when frozen.

"Unfortunately, the grand diversity of naturally occurring snow crystals is commonly corrupted by incorrect 'designer' versions," chemist Thomas Koop of Bielefeld University in Germany writes in a brief missive to Nature published in the December 24/31 issue. (Scientific American is part of Nature Publishing Group.) As Koop points out, the six-sided nature of snowflakes has long been known. In 1611, for instance, German astronomer Johannes Kepler presented his patron with a unique gift to mark the new year: a treatise called On the Six-Cornered Snowflake.

One researcher who would likely second Koop's complaint is Kenneth Libbrecht, a physicist at the California Institute of Technology. Libbrecht maintains snowcrystals.com, a Web site devoted to snowflake photography and physics; the site even features a "morphology diagram" that shows how humidity and temperature converge to direct the formation of various snowflake types—all of them hexagonal. See some of Libbrecht's photographs, which show natural six-cornered snowflakes to be as intricate and lovely as anything an artist could dream up, in this 2008 slide show.

Nevertheless, the counterfeit flakes continue to proliferate—including, as Koop notes, in Nature's own advertising campaigns. "We who enjoy both science and captivating design," he writes, "should aim to melt away all four-, five- or eight-cornered snow crystals from cards, children's books and advertisements." But, despite his holiday grievance, the chemist is no grinch: "Let's welcome this as an opportunity to share a discussion about the true beauty of science over a mug of hot punch."

An example of an offending "designer" snowflake: ©iStockphoto/magicinfoto