City Block was
Dave Litwin’s IPP33 Exchange Puzzle – it’s a collaboration with Bram Cohen (who
also happened to design Cast Marble, my all-time favourite Hanayama puzzle) and
there’s a fantastic interview with Dave and Bram on Saul Symonds blog over here. Well worth a read!
The puzzle presents you with a set of building-shaped
pieces, complete with cut-out windows, which you are first challenged to arrange
in the silhouette of the cityscape printed on the top of the tray (described by
Dave as a warm-up challenge – which feels about right) – the next challenge is
to fit all of the pieces inside the tray … including the one that has its own
space outside the tray to start with.
It’s a fun challenge and despite having solved it a while
ago, I’d totally missed the elegance of the solution that Saul’s interview
hints at – so I went back and solved it again and indeed, there’s a rather
pleasing feature to the solution that I’d totally overlooked!
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Jerry Slocum’s exchange puzzle this year was a Stewart
Coffin design called Cracked Egg.
It is evil.
Coffin’s tray-packing puzzles are usually pretty darn mean –
even when you get a perfectly square tray (because you can basically ignore the positioning
of the eventual solution) they’re hard. In my mind they get harder when he
changes the shape of the tray and tosses in some funky angles (Lean 2 anyone?) – but when he gives you an oval tray with no straight edges at all, in
my mind he’s just gone and given you an almost infinite number of orientations
to check. Even with Stewart’s helpful little words of advice on the back of the
tray, STC #260 X-1 is still a very serious challenge.
I’d spent ages working on this one on and off since IPP and
if it hadn’t been for Louis solving it on one of his visits, I probably still
wouldn’t have it neatly packed in the tray.
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Occam’s Razor was
Vladimir Krasnoukhov’s exchange puzzle. A neat little acrylic tray-packing
puzzle with one large piece (a razor?) starting out in its own little
compartment in the tray – your aim is to pack all of the pieces into the
main section of the tray…
This one’s interesting because the main section of the tray
starts out with all the pieces on the diagonal … knowing these sort of puzzles,
and having seen one or two of Vladimir’s others designs, I merrily set off down
the path I thought was likely to be most fruitful … and spent quite a long time
exploring it without much luck at all … eventually I went off on another tack
and this time managed to achieve something interesting and found that there was
just enough space left to slot the razor-piece into the tray … fun little
puzzle where the name makes sense on all sorts of levels.
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Houses and Factories
2 was Dick Hess’ exchange this year. It extends the original Houses and
Factories puzzle and provides a set of really good challenges.
You’re given a square frame and three types of pieces:
houses (roof with no chimney), small factories (roof with small chimney) and
large factories (work it out yourself!). The instructions give you three
challenges to fit respective sets of six pieces inside the frame.
Those challenges are excellent – I found myself spending hours
spread over several weeks fiddling around with them from time to time – and getting
a huge sense of satisfaction whenever I managed to get a set of pieces to fit
in the frame. The solutions are all pretty different, so having solved any one
of them doesn’t really provide much help on solving the others… 
