What's with the different colored lights that illuminate the towers of the USA Today building in Tysons Corner? I'm sure there's a rhyme or reason as to why one day the towers are bathed in green light, purple the next, yellow another, red and even white. Does it have something to do with the weather forecast, or is it just random?

Matt Fetters, Gaithersburg

Answer Man has heard a theory about this: The lighted towers indicate which cartridges of ink need changing in the gigantic printer that produces USA Today. The press operators need only glance upward to see whether they're running low on cyan, magenta, yellow, black or photo black.

As with so many theories (intelligent design, the Atkins diet), this one is preposterous. The colors actually indicate which section of the paper USA Today Editor Ken Paulson happens to be reading at that particular moment: blue for News, green for Money, red for Sports or purple for Life.

Answer Man is kidding. The colors are, in fact, random, said USA Today spokeswoman Heidi Henderson.

"It's funny to hear what people think it might be," she said. "I think people just assume it's the USA Today colors because you go by and it's blue, and then you go by and it's purple. But it's definitely random."

Well, not always random. One day in February, the towers had a crimson cast in honor of Go Red for Women, a campaign to raise awareness of heart disease. Or, as the Guess Who sang: "Colored lights can hypnotize/sparkle someone else's eyes." ("American Woman." Colored lights. Heart disease. Get it?)

The Washington area has seen a mini-explosion of interesting lights recently. In addition to the USA Today building, there's 1625 I St. NW downtown and Discovery Communications' building in Silver Spring.

"I think in the last few decades architects have started to think of lighting as architecture," said David King, chairman of Smith Group, the firm that designed the Discovery HQ.

In the past, only a few important buildings -- the courthouse, a church or synagogue -- were illuminated with bright, white light, said David. But with improvements in bulbs, light-emitting diodes and computer controls, almost any building can throb like the disco floor in "Saturday Night Fever."

Last week, Answer Man climbed a ladder to enter the big, frosted glass cube atop 1625 I St. Inside were 580 4-foot-long TerraLux 32-watt fluorescent light bulbs, stacked vertically in rows of four. White, green, red and blue bulbs repeated in near-endless succession. By adjusting the relative brightness of each bulb, chief engineer Joe Swann can produce just about any color.

When the building opened in 2003, the colors changed slowly over the course of an evening, like a gigantic mood ring. But, said Joe, "When the building sold, they preferred a solid color." And that solid color is a medium blue -- Brookfield blue, to be exact, named after the company that bought the building.

As with USA Today's towers, the box changes on special occasions. "When the Red Sox won the Series, we made it red for a week as a tribute," said Joe. Right now, Joe and his assistant, Russell Garner, are making sure no green bulbs are burned out because they'll do green and red for Christmas.

The Discovery building has the area's friskiest lighting. Two sets of LEDs -- in a tower and above the main entrance -- glow and occasionally chase each other.

Although the attractive lights have no literal meaning, that was considered, said designers Rodrigo Manriquez and Jeff Gerwing.

They pitched the cable company on having the lights reference upcoming programs: an icy, Arctic blue during the "Raise the Mammoth" period, for example, or a fiery yellow and red for a program on asteroids.

Hey, maybe they could do the terror alert level.

Fire and Water

Grill-happy readers continue to weigh in on why The Post seems to burn differently at different times. Maybe it's the humidity, someone said. Wheaton's Alan Lichter, who uses The Post to get his charcoal briquettes a-burnin', has a different theory.

Wrote Alan: "After several experiments over the summer my conclusion is that the color ink used in photographs is a deciding factor. If I was careful to only use pages that have only black ink the paper burned cleanly and ignited the charcoal. When I use color ads or pages with color pictures, then the paper does not burn as well, or even completely, and the charcoal doesn't get going."

Sadly, this will all be moot soon as winter forces even the hardiest barbeque fans inside their homes, from which they will stare wistfully at the Weber grill buried under a mantle of snow.

From one element to another: In the early 1960s, Edward Guerrero of Great Falls was a volunteer swimmer for the Red Cross and worked on the President's Cup Regatta, the speedboat race mentioned in this space a few weeks ago.

"One year, the front of Miss Budweiser's boat went underwater at a high rate of speed," Edward wrote. "The boat broke up and the driver went airborne. Another swimmer and I jumped in and got him out. He was very much alive. After the driver was taken away, we were taken to the Presidential yacht the Sequoia for showers, as the Potomac River was quite polluted then."

Boy, I hope they kept their mouths closed.

Julia Feldmeier helped research this story. Send your questions about the Washington area to answerman@washpost.com, or write John Kelly, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071.