It’s always a bit worrying to find that all of the Sunday comic artists have agreed to have a similar theme for a day’s strips. It happens naturally on Christmas, Halloween, New Year’s or the Fourth of July.

But sometimes they agree to all address a single issue – as if they all work in a single, large factory floor slaving over their four-color creations.

Once it was about hunger, another time, in a much more lighthearted move, they all decided to draw or parody each other’s work in honor of April Fool’s Day (the details are hazy in my mind).

On Sunday, they all addressed a much more difficult topic: The 10th anniversary of 9/11.

You will remember how difficult it was for professional comedians to come up with material or even face audiences after the initial terror attack. Late night shows were canceled for days, and when they returned it was often with tears and an uncomfortable seriousness.

Finally, they got their footing when they found that making fun of, say, the media coverage of the tragedy opened up a fair field for them to comment (the “Daily Show” is especially good about this).

Still, late night comedy is a long distance from the Sunday comics page and the family audience it gathers. So it might have taken 10 years for cartoonists to address it.

And when it happened, some of it was mawkish. In Beetle Bailey, all the characters just wept (“All of us are suffering for the friends and families of those who were killed”).

The cast of “Blondie” stood around a flagpole and saluted, with the caption “Never Forget.”

It was only too easy for Jeffy to pray for mom, dad, grapndparents, siblings and oh yes, the world.

Mr. Wilson pauses in his criticism of Dennis the Menace’s noise because he’s leading a National Day of Service and Rememberance parade.

The characters of Brewster Rockit, Sherman’s Lagoon and Prickly City stood in attention at the Tribute of Light at Ground Zero.

Mark Trail, of course, surrounded himself with the bald eagle and saluted those lost and injured.

But it was a shock that the comic strip Lio, which prides itself on being wordless, being a panel of its character (and the artist?) with the phrase “A toast to the memory of those who were lost ten years ago today.”

Mary Lane reminisced about lost ones on the phone; an engagement on Apt. 3-G is interrupted by incongruous banner honoring the memory of 9/11.

Others found a way to incorporate the sentiments more organically into their regular storylines as when Hagar the Horrible explains to his son what a hero is, ending the strip with “Remember our heroes!” next to a larger than usual date, 9-11.

Tank McNamara for his part stopped talking his regular topic to realize “Putting sports on the scale of things, silence would be good today.”

The best strips found a way to both be funny (or at least wry) while clearly noting the anniversary. In Zits, the beleaguered teenager caught in a single panel cartoon of his parents close embrace says “Seriously, do we have to do this every September 11th?” perhaps referring to the cartoonists’ pact as well.

In both Baby Blues and Big Nate, there is an almost edgy reference to a pair of towers – one of blocks, another of sand, that defy being knocked down. Marvin also builds some towers out of remembrance.

The dog in Mother Goose & Grimm gives way to the firemen who are also approaching a red fireplug. “It’s the anniversary of 9/11…Please You First.,” a gag also used in Pooch Café.

“Heal,” says the dog in Mutts.

Doonesbury for its part didn’t have to have its arm twisted to be topical. It has B.D. urging Zonker not to turn on the TV and its round the clock memorial coverage.

“Thousands of people watched those buildings come down. Thousands more worked the pile. If you were there, you don’t need to be reminded of what happened. We get to relive it every night,” B.D. says. “Go see ‘Cowboys & Aliens’ instead. Something that makes sense.”

Shoe complained about security. “By next season we’ll need a thorough pat-down to watch the Travel Channel,” he complains.

The stool-riders at a diner in Zippy lent a wish: “Here’s hoping democracy works out in Egypt,” “…and Libya…and Syria…and Tuniais” “and here.”

Another comic went even further, something to be expected when the strip is called Candorville.

“What were you thinking bout when you went to bed on 9/11?” says one man to a female companion.

“I was praying I’d wake up the next day and it’d all be just a dream.”

The guy answers: “I was hoping we’d rise to the occasion and honor the dead, the survivors and the heroes … by failing to rebuild the twin towers, by curtailing our own civil liberties, by calling eachother “un-American,” by torturing prisoners, mocking the French, invading the wrong country and having our airports inspect kids’ and old people’ underpants.”

“I like to have realistic hopes,” he concludes.

His companion replies: “I don’t think sarcasm’s allowed on 9/11 Day.”

A bunch of the cartoons are collected here.