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These are the ramblings of Matthijs Kooijman, concerning the software he hacks on, hobbies he has and occasionally his personal life.

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Day 3: Puzzles

Coffee We received two initial clues: a paper stating "Koffie, koffie, lekker bakkie koffie, wat knapt een mens daarvan op" ("Coffee, coffee, nice cup of coffee, it does a man good"). The second clue were wooden tangram pieces, with lines drawn on the back and two holes in them.

We spent a good deal thinking about the coffee thing, which were lines from a song by Rita Corita. We had a lot of vague ideas, but none of them were really solid, or turned up new clues. The hint suggested that the second part of the hint was not a statement but a question, which we had already considered. So, long story short, we got nowhere.

Horst The tangram pieces were easier. When you put them in a normal tangram square, the backside would show a top view of the "Horst" building. Interpreting the holes as locations to find clues turned out nothing, but just searching the Horst entrance found us a clue (but only at the second try...).


Tangram The clue found at the horst were six tangram problems, which would clearly need to be solved. Fortunately, Elvan had some experience with these, so within minutes, we had six solved tangrams on photo. To turn these solved tangrams into a clue, one needs to lay them out one by one. You start with laying down the first tangram. Now, we remove all pieces, leaving only the triangle with the hole on the table. We mark where the hole is.

Next, we lay down the second tangram around the triangle, leaving it where it is. When we're done, we remove all pieces except for the paralellogram with the hole. Again we mark the location of the hole. Now, we lay down the third tangram, around the parallelogram. Again we remove all pieces, this time leaving only the triangle again, and marking its position. If we continue this and connect the dots, we will get the figure of an "L" turned counter clockwise, which is an "L on its long side", translating to the "Langezijds" building. If you think "Wtf?!", you should click the image below, which will take you to a nice animation of this method (courtesy of Ieniemienie, thanks!).

Animation We had considered this solving method quite soon after solving the six tangrams, but we encountered a problem in the orientation. Neither the triangle or the paralellogram were oriented in the same way in tangram 3 and 4. For this reason, we discarded this method. It turns out that tangram 3 is slightly ambigious, the holed triangle and a small triangle form a figure that is symmetric, so can be mirrored, changing the orientation of the triangle. So, we were close, but not there yet.

After some hours of puzzling, the organisation gave away the answer to the tangram puzzle: the Langezijds building, since the tangram was too hard. Even then it took us a lot of time to actually find the clue, since it was not near the main entrance and Langezijds is a huge building. But, we found it eventually.


Fishy At Langezijds we found a picture of a (yellow) boxing glove together with a (yellow) fish. This one is rather easy when you do some research. Googling around for this particular type of fish, turns you to the family of "boxfish" (hence, the boxing glove). Boxfish are fish that are cubic in shape. This particular species of boxfish is called the "Yellow Boxfish", or Ostracion cubicus. Coincidentally, we have a building on campus called "Cubicus", which is where the next clue was hidden.

This is where the chronology of this story breaks. In reality, we had found the Cubicus clue hours before, after noticing the Inter-Actief bestuur team sneaking around Cubicus very conspicuously. We did solve the puzzles leading up to here in paralell with the puzzles from this point on, though.


Miffy The next clue was a peculiar one: A sequence of numbers together with the cartoon figure "Miffy". Our initial association with Miffy was the "Vlinder", a kinder garten on campus. Our second try was the book store, since Miffy was drawn by Dick Bruna, whereas Bruna is a chain of bookstores (little far-fetched, but one can try, no?).

The next association with Miffy, being a rabbit, was Fibonacci. The Fibonacci sequence was originally created to model the growth rate of rabbits. After some number crunching, Elvan, our Fibonacci specialist, came back with the answer: If you take each number and subtract the two preceding numbers from the sequence, you will get numbers between 1 and 26. Translating the result through 1=A encoding gives "blokhutten" ("cottages"), which we have on campus.

Linear algebra

Linalg The next clue were a number of lineair equations, with weird symbols instead of numbers. This was an easy one: Assign a number to each symbol in such a way that the equations work out. There were three sets of symbols: Japanese-ish, Russian and Greek. Within each set of symbols, no number could be assigned more than once.

So, the method was easy. But solving the problem proved harder. Eventually I discovered an internal inconsistency in the puzzle, which got corrected by the organisation. While struggling with these equations, I wrote a small prolog program to solve the bottom two sets of equations (the top one was correct and solved by hand).

Now, with a mapping from symbols to numbers, the line of symbols at the bottom can be translated to a telephone number. Calling this number gave me a very weird voicemail, which turned out to be the wrong number. Luckily I did not awake some random poor soul with my phonecall. After the organisation corrected this mistake, I called the correct number: 06 18691667. Calling this number turned up a voicemail message of the powerpuffs, pointing to a file on the internet. This file contained the files that the powerpuffs had stolen on the first day, together with some evidence suggesting that Pandaprijs is involved with drug smuggling. Something to think about...

But, among the stolen files was a file that contained the password of the final day 3 puzzle. When submitting this answer, we got confirmation that was correct. We had finished the puzzles succesfully. We missed out on the "coffee" puzzle line, but we ended up where we wanted to be anyway.


This time, finally, we managed to submit the correct solution first. The plumbers were on our tail: they submitted within 6 minutes after us. After this, nobody really solved the puzzles. A few more teams submitted the correct solution, but after we had sent them the rar file we found. Because the organization seems to be using us as cover up for drug smuggle, we decided to pass the files around so people might get together and act. Perhaps open rebellion?

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