# Can You Solve This UK Intelligence Agency’s Puzzling Christmas Card?

This season, Britain’s secretive spy agency the Government Communications Headquarters, or GCHQ, has sent out some rather peculiar Christmas cards. Instead of greetings full of merriment and joy, they presented a challenging puzzle for anyone bold enough to attempt to solve it.

The puzzle consists of a grid with select blocks shaded in and series of numbers along each axis. Once code-breakers solve the initial problem, they’ll be left with an image that leads to "a series of increasingly complex challenges." The agency explains how to tackle the puzzle:

“In this type of grid-shading puzzle, each square is either black or white. Some of the black squares have already been filled in for you. Each row or column is labeled with a string of numbers. The numbers indicate the length of all consecutive runs of black squares, and are displayed in the order that the runs appear in that line. For example, a label '2 1 6' indicates sets of two, one and six black squares, each of which will have at least one white square separating them.”

If you weren’t lucky enough to make it onto GCHQ’s mailing this year, you can take a crack at the puzzle below or download a high resolution version by going to their website. The agency’s director is asking for anyone who completes the challenge to send in their work by the end of January 2016 so they can select a winner. Apparently the email address you need to direct your answers to is revealed in the puzzle, so you’ll know when you’ve qualified. The GCHQ also asks that anyone participating make a donation to the National Society for the Prevention of Cruelty to Children this holiday season.

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Want to Recycle Your Christmas Tree? Feed It to an Elephant
Sean Gallup/Getty Images

When the holiday season finally comes to a close, people get creative with the surplus of dead Christmas trees. One San Francisco-based artist transformed brittle shrubs into hanging installation pieces. Others use pine needles for mulch, or repurpose trees into bird sanctuaries. For the average person, sticking it into a wood chipper or "treecycling" it as part of a community program are all eco-friendly ways to say goodbye to this year's Douglas fir. None of these solutions, however, are as cute as the waste-cutting strategy employed by some zoos around the world: giving them to elephants.

Each year, zookeepers at Tierpark Berlin—a facility that bills itself as “Europe’s largest adventure animal park”—feed the elephants unsold pine trees. The plants are reportedly pesticide-free, and they serve as a good (albeit prickly) supplement to the pachyderms' usual winter diets.

A bit closer to home, the residents of The Elephant Sanctuary in Hohenwald, Tennessee rely on local residents to take part in their annual Christmas Tree Drive. In addition to being nutrient-rich, the tree's needles are said to help aid in an elephant's digestion. But beyond all that, it's pretty adorable to watch.

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5 Eco-Friendly Ways to Dispose of Your Christmas Tree
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What’s the environmentally safest way to dispose of your Christmas tree? It’s hard to say. Grown, managed, transported, and recycled efficiently, a real Christmas tree’s environmental impact should be near neutral. Unfortunately, not all Christmas tree plantations are equal in their environmental impact.

The most eco-friendly way is to leave the tree in the ground, where it belongs, so you never have to dispose of it. But then you don't have a Christmas tree in your house to bring festive cheer. One thing you can do is be environmentally smart when it comes to the tree's disposal. After this festive season, why not try one of these eco-friendly methods.

#### 1. CHIP IT.

If you’re lucky enough to have access to a big wood-chipper, you may be able to chip the entire tree. Wood-chip is great as a decorative landscaping material. But if you really want to do great things for the environment (and if you have access to a lot of Christmas trees), you could make a bioreactor to denitrify water. Nitrates are put on farms across the world to help increase crop output, but a considerable amount is washed away into lakes and rivers where it’s disastrous for fish and potentially toxic for people. A wood chip bioreactor encourages the growth of bacteria that break down the nitrates in the drainage water, reducing the amount that gets into the water supply. It's not a simple project, however. To make one, you have to dig a big trench, get the water to flow through said trench, and fill it with wood chips. More info can be found here [PDF].

#### 2. CRAFT IT.

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If your tree hasn’t yet let go of its needles—and you haven’t yet let go of Christmas, get crafty with it. Cut off small branches and bind them around a circle of wire to make an attractive wreath. This looks even better if some of the cones are still attached. If you’re feeling really adventurous, you could set up an essential oil extractor to get a supercharged Christmas scent. If you are already distilling alcohol, you have everything you need (here's how to do it). With a little less effort and equipment, you can make a weaker liquid called hydrosol, which is a fragrant condensate water containing water-soluble parts of the needles.

#### 3. STICK IT.

Many legumes, such as garden peas, are thigmotropic, meaning that they respond to objects they touch, growing in coils along or up them. Needle-free Christmas tree branches have lots of twigs, texture, and knobby protrusions for peas and beans to get a grip on. This allows them to grow upwards strongly toward light. Simply stick a small tree branch in the soil next to each new shoot for a free, effective legume-climbing frame. Another advantage of this technique is that it makes grazing animals less likely to munch those tender green shoots, as they tend to avoid getting Christmas tree twigs spiked up their noses.

#### 4. TREECYCLE IT.

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Come January, it’s cold, the festivities are over, work looms, and you’ve got too much on your mind to be thinking about dead Christmas tree horticulture or crafts. Fortunately, a simple solution is at hand: Most counties and municipalities now provide Christmas tree recycling points where you can take your tree for chipping. Some “TreeCycle” points will even exchange your tree for a bag of wood-chip or chip mulch. OK, this probably means that you’ll have to jam that Christmas tree into your car once more, but as long as you don’t have to drive too many miles out of your way, Christmas tree recycling is a quick and easy environmentally-friendly option.

#### 5. DONATE IT.

After you’ve had your Christmas cheer, why shouldn’t fish have some fun? Several communities have programs in place where they’ll take your old Christmas tree, drill a hole in the base, tie a brick to it, and throw it in a lake. When humans create artificial lakes, they tend to be relatively featureless on the bottom for easy dredging. That’s great for us, but it means baby fish have nowhere to escape predators. Christmas trees provide a nice, temporary place for the fish to hide out and explore.

If, on the other hand, you’d like to see your Christmas tree mauled by a pride of lions, that’s OK too! Some zoos around the world take Christmas tree donations (but please remove all the tinsel first) and allow the animals to play with them.

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