__Blood-spurting martyrs, biblical __parables, ascendant doves — most church windows feature the same preachy images that have awed parishioners for centuries. But a new stained-glass window in Germany's Cologne Cathedral, to be completed in August, evokes technology and science, not religion and the divine. Contemporary German artist Gerhard Richter designed the 65-foot-tall work to replace the original, destroyed by bombs in World War II. As a starting point, he used his own 1974 painting 4096 Colors. To create that piece — a 64-by-64 grid of squares — Richter devised a mathematical formula to systematically mix permutations of the three primary colors and gray. Funny coincidence: 4,096 is also the number of "Web-smart" colors that display consistently on older computer screens, a limitation some Web designers still take into account. (Today's monitors, of course, can handle pretty much any hue.) The Cologne window is made of 11,500 four-inch " pixels" cut from original antique glass in a total of 72 colors. Why not 4,096? Turns out there are stained glass-smart colors, too. Some hues in Richter's initial design were either historically inaccurate or too pale — they would have outshone the squares around them. So the artist modified his palette to include only colors with a suitably archaic cast. Because it's fine for a church window to look like it's been designed by a computer, as long as it's a computer with a gothic sensibility.

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