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Philippe Suter

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My puzzle game Tileswap made it to the iOS app store. You would be most welcome to enjoy, rate, review, and share!


Look at that, I made an Android game! Try it out in your browser or on your phone:

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I'm not generally one to resist changes in user interfaces. I must have seen 20 different interfaces for Facebook, for instance, 5 or so for Google+, etc. The modifications are rarely revolutionary, sometimes they are annoying, but in general I forget that something has changed a day or so later.

The integration of hangout in GMail, however, is a different story. Never mind that it has gotten harder to see who is online, that the emoticons are the ugliest I have ever seen (and I have witnessed custom smiley extensions in the MSN age), or that in the process Google has dumped XMPP support. No, the real issue is that I cannot input little dancing crabs anymore.

Fortunately, it is, in fact, very simple to revert to the older chat widget. Just click on your own name, and the option is right there: "revert back to old chat".

We all know how this is going to end, though. One day, I will log in, and will be greeted with a "new, better, GMail" message, telling me how my "experience has improved", offering a "tour of new features", and the old chat will be gone forever. Until that day comes, I will enjoy every single of my dancing crabs V.v.V.

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Work by my colleague +Mikaël Mayer  programming by live interactions with the game simulation.

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UTF-8 turned 20 years old yesterday.

It's been well documented elsewhere ( that one Wednesday night, after a phone call from X/Open, Ken Thompson and I were sitting in a New Jersey diner talking about how best to represent Unicode as a byte stream. Given the experience we had accumulated dealing with the original UTF, which had many problems, we knew what we wanted. X/Open had offered us a deal: implement something better than their proposal, called FSS/UTF (File System Safe UTF; the name tells you something on its own), and do so before Monday. In return, they'd push it as existing practice.

UTF was awful. It had modulo-192 arithmetic, if I remember correctly, and was all but impossible to implement efficiently on old SPARCs with no divide hardware. Strings like "/*" could appear in the middle of a Cyrillic character, making your Russian text start a C comment. And more. It simply wasn't practical as an encoding: think what happens to that slash byte inside a Unix file name.

FSS/UTF addressed that problem, which was great. Big improvement though it was, however, FSS/UTF was more intricate than we liked and lacked one property we insisted on: If a byte is corrupted, it should be possible to re-synch the encoded stream without losing more than one character. When we claimed we wanted that property, and sensed we could press for a chance to design something right, X/Open gave us the green light to try.

The diner was the Corner Café in New Providence, New Jersey. We just called it Mom's, to honor the previous proprietor. I don't know if it's still the same, but we went there for dinner often, it being the closest place to the Murray Hill offices. Being a proper diner, it had paper placemats, and it was on one of those placemats that Ken sketched out the bit-packing for UTF-8. It was so easy once we saw it that there was no reason to keep the placemat for notes, and we left it behind. Or maybe we did bring it back to the lab; I'm not sure. But it's gone now.

I'll always regret that.

But that's my only regret in this story. UTF-8 has made the world a better place and I am delighted to have been a facilitator in its creation.

So tonight, please give a toast to a few quickly sketched boxes on a placemat in a New Jersey diner that today define how humans represent their text to be sent across international boundaries (, and especially to the X/Open folks for giving us the chance and the Unicode consortium and IETF for pushing it so successfully.

U+263A '☺' white smiling face

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I was looking for the LLNCS instructions and found an old version; exact date unknown, but url is

Acceptable formats of your disk/magnetic tape and output:

The following formats are acceptable: 5.25" diskette MS-DOS, 5.25" CP/M, 3.5" diskette MS-DOS, 3.5" diskette Apple MacIntosh, 9-track 1600 bpi magnetic tape VAX/VMS, 9-track 1600 bpi magnetic tape ANSI with label, SUN-Streamer Tape.

Once you have completed your work using the macro package, please submit your own printout of the final version together with the disk or magnetic tape, containing your LaTeX input (source) file and the final DVI-file and make sure the text is identical in both cases.

This macro package, as well as all other macro packages, style files, and document classes that Springer distributes, are also available through our mailserver (for people with only e-mail access).; first try the help command.

We are also reachable through the world wide web:
URLs are, gopher://,

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Kids get exposed to string theory early, these days.
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