Monthly Archives: March 2014

Most difficult chess problem

Posted on March 28, 2014 by apgoucher

Neil Bickford has exhaustively searched the space of 5 × 4 sliding-block puzzles* to determine the one with the longest minimal solution. The unique result, which requires a whopping 235 moves, happens to be Bob Henderson’s Gauntlet puzzle: *subject to the … Continue reading →

Posted in Chess | 27 Comments

Cipher 62: Also untitled

Posted on March 25, 2014 by apgoucher

By the way, we’ve raised £463.00 so far for the Schistosomiasis Control Initiative (see this post for an explanation). This week’s cipher uses a couple of relatively simple ideas, although I could imagine it being difficult to cryptanalyse. DKGOQXIWSASPYKOWEEPLELTLELFSKTPITLJFCLXSANZRYYNTAAJDQC Good … Continue reading →

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Denser packing of pound coins discovered

Posted on March 20, 2014 by apgoucher

Until very recently, the densest known packing of pound coins in the plane was the hexagonal lattice packing of circles, which achieves a density of π/√12 ≈ 0.9069. This was proved by Axel Thue to be the densest arrangement of … Continue reading →

Posted in Uncategorized | 7 Comments

Cipher 61: Discrepancy

Posted on March 17, 2014 by apgoucher

Slightly less major announcement: Stuart Gascoigne has now solved a total of 50 ciphers, earning the first ‘gold star’ icon on the solvers page. 00111101 11011100 11110011 00111110 00010110 11011110 00100000 11010111 10000001 00001000 11010111 10111111 11101101 00101110 11111010 00111110 00000010 10110001 … Continue reading →

Posted in Ciphers | 3 Comments

Rectangular hyperbolae and the orthocentre

Posted on March 16, 2014 by apgoucher

Firstly, a major announcement: Maria Holdcroft (whom you may remember from the cipher solvers page) and I will be performing a charity skydive on the 2nd April! If you wish to sponsor us, please specify the amount you intend to donate by commenting … Continue reading →

Posted in Uncategorized | 1 Comment

Cipher 60: Tuesday comes between Wednesday and Friday this week

Posted on March 13, 2014 by apgoucher

The more astute observers amongst you may have noticed that this particular cipher is two days later than is usual, as a consequence of a particularly busy week. Hence, I had no choice but to officially postpone Tuesday by 48 … Continue reading →

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Emergence

Posted on March 7, 2014 by apgoucher

One of the most miraculous phenomena in the universe is, unarguably, the existence of biological life. Whilst evolution nicely accounts for the gradual progression from the earliest archaeobacteria to the vast array of multicellular creatures capable of astounding feats of … Continue reading →

Posted in Uncategorized | 3 Comments

Cipher 59: Iterated question-answering

Posted on March 3, 2014 by apgoucher

This is another particularly satisfying one to solve. XGJDGSZUIDSSDDDOURPMHDNOUZJMTBMVNAFQTVBISIBSUIDS HOHNGHOUDHFQTHOUGFOTNAFSEJDMEFFODSZUFCCZHUEPSLBM JOSFHQBKEPLBHOUGBUHTDVDKJEDBMCVSONUONSNDVBMJCFZO Good luck. As usual, the password is in lower-case and contains no punctuation. Also, it is precisely twelve letters in length.

Posted in Ciphers | 2 Comments