The Code

The Code is a three-part TV series about maths in the natural world, presented by Marcus du Sautoy, that aired in July 2011. Why do bees make hexagonal honeycomb? Where’s the best place to stand to get on a train first? How can dozens of wrong answers make a correct one? The secret lies in The Code...

That not all, because The Code was also a treasure hunt! We hid clues in each episode of the show as well as in a series of online games and on our blog, and in the summer of 2011, viewers from across the UK dived in to find out where we'd hidden a secret treasure. Our three finalists - Helen Bennett, Pete Ryland, and Dave McBryan - battled it out at our Finale in Bletchley Park, with Pete Ryland pipping the others to the post.

But while the hunt is over and the treasure found, you can still replay the treasure hunt online! And if you're stuck, check out our Treasure Hunt Tips.

Check out the Treasure Hunt to find out how to play The Code. Please remember that the treasure has been discovered and so while you can replay all the games and puzzles, you can't actually win the treasure.

Each episode contained three clues, and we've made sure that each of those clues is still viewable via short clips on The Code's Programme Page.

At present, there are no plans to release a DVD of The Code. However, we are putting together a specially-edited version of the show for schools; we'll have more information on that soon.

You will only know if you’ve got the right answer when you try to unlock the Ultimate Challenge by entering your three passwords. If you are unable to unlock the Ultimate Challenge, you’ll know at least one of your answers is wrong.

Not at all! Most of The Code treasure hunt is accessible to people of all ages and skills; you certainly don’t need to be a maths genius to take part and have fun. Of course, as the treasure hunt goes on, it does get harder - particularly during the second stage of the game - but there’ll always be something for everyone to solve!

The games, puzzles and challenges that make up the treasure hunt are suitable for all ages and don't have any age restrictions.

All you need is a computer that can surf the web and play Flash games! Playing the Flash games and online puzzles in the treasure hunt is also completely free.

You need to register with BBC ID to get a username in order to comment on the blog.

The Ultimate Challenge is an 84-page book containing a series of puzzles that will test your imagination and wits! To access the challenge, you'll need all three Codebreaker passwords.

Windows: You may need to download Adobe Acrobat Reader to view the PDF.

Apple Mac OS X: Double-click the file to open it in the Preview application.

The Finale was an event held at Bletchley Park on September 10th 2011 for the first three eligible people to complete the Ultimate Challenge. Watch what happened at the Finale online!

Before the show aired, we printed 1024 individual postcards and sent them to people around the UK. Each postcard contained a puzzle and an image that viewers discovered was a slice of our treasure. Find out more on our blog...

The Code was produced in-house by BBC Factual and BBC Multiplatform, with Six to Start and Marcus du Sautoy creating the online and treasure hunt components.

If you're stuck in the treasure hunt, have no fear, we're here to help! The Codebreakers are the key to unlocking the hunt, so let's start at the...

Episode 1 Codebreaker

When you load this up, you'll see what looks like a clock with six hands on the left, and six questions on the right. Each of those hands corresponds to one of the questions, and you can tell which is which by looking at the number on the hands. What you need to do now is to click and drag each of those hands to the correct answer for each question; so, it's a bit like a big multiple choice quiz!

Let's tackle the first 3 questions together, since they're all to do with clips from the show. We've provided links to the relevant clips in the right hand column of the clues below the Codebreaker. The clue that 'hides in Pi' is in the video clip about Pi, and you can find the number when Marcus talks about 'the answer to Life, The Universe, and Everything. The next clue 'in the stars' is in the clip about stars and prediction, and if you watch the skies carefully, you'll see a number appear! And the third clue about 'what will next sing in 2024' is in the video clip about Cicadas - just listen careful to what Marcus and Dr. John Cooley are saying...

Question 4 is about the Cicada Survival Puzzle, and obviously the answer must be a number. Check out the comments below the blog post for tips. Question 5 is within Level 5 on Prima Pizzeria, but if you really can't solve it, it's something to do with rodents... Finally, Question 6 was solved by the players in July so you can just see the answer here - ARCHIMEDES!

Episode 2 Codebreaker

Things are a little bit harder here. Question 1 refers to the Giant's Causeway clip - if you watch it carefully, there's a moment when the hexagons are highlighted in purple and you can see symbols appear within them. If you freeze the clip at the right time, you'll notice that it's a maze. Find your way through the maze and see what word you spell out...

Question 2 is about the Platonic Solids dice clip. On each dice, a certain number has been replaced with the symbol Phi. You need to figure out what that number is - just watch carefully to see which number doesn't appear. And Question 3 is pretty straightforward, but we'll give you a hint: the answer starts with 4!

The Strange Dice puzzle in Question 4 is a bit trickier. If you can't visualise what the dice look like in 3D, it's worth trying to construct them in paper and figuring out the relationship between numbers on opposite faces of each die. Think of shapes, like squares and cubes...

Question 5 is given to you at the end of Master of Mosaics (but here's a hint - it's the name of a famous Indian mathematician) and Question 6's answer, courtesy of the Prime Number Hunters, is GAUSS.

Episode 3 Codebreaker

This is the trickiest Codebreaker of them all. Question 1 is all about the Google clip - if you watch it carefully, about 1:30 in you'll see a rather strange search term appear. Type that term into Google and you'll see that it links to a hidden video on YouTube. Watch that video and you'll find your answer.

Question 2 refers to the starlings flocking behaviour clip. You can sit back for this one - just watch and see the strange pattern the flock turns into towards the end. And Question 3 is about the Rock, Paper, Scissors clip. In the clip, you'll see a hand with dots painted on the nails. What do they look like, and what might they spell?

Question 4 is about the Search Logic puzzle. To solve this one, just take it step by step with the answers that you definitely know - you'll want a piece of paper to keep track of your thinking though! And if you get really stuck, check the comments.

Question 5's answer is in Level 6 of Kingdom of Catapults - keep an eye on the text below the castle where the Code Facts normally are (and if you can't get that far, it's a famous German mathematician). Finally, Question 6 is the last part of the Prime Number Challenge, and the answer is LAGRANGE.

The Ultimate Challenge

So, now you should have your three passwords! Download the Ultimate Challenge PDF and try to unlock it. Please remember that if your answers were ALICE, BOB, and CHARLIE you must type in ALICEBOBCHARLIE - "alice bob charlie" or "alicebobcharlie" will not work.

If you aren't getting anywhere with it, here's a hint: the Ep 1 Codebreaker starts with P and ends with S; the second password starts with A and ends with S, and the third password starts with P and ends with G. That should tell you where you might be going wrong.

And now things get much more interesting! If you need help with the Ultimate Challenge, check out the fantastic unofficial Crack The Code wiki the players made, and specifically the How To Crack The Code guide. We'll also be putting up a blog post in the near future with the answers to all the puzzles. Good luck, and have fun!

Just email us at code@bbc.co.uk if you have any extra questions.