blake johnson

In an effort to encourage reader participation, I bring to you my first ever blog riddle. This riddle was told to me by Mike Metcalfe over dinner during the March meeting.

There was an evil king that wanted to kill 4 of his subjects, but worried that there would be an uprising if he simply had them executed, he decided to provide them with a way to escape their fate. What he did was to bury each of them in the ground up to their neck and he put a white or black hat on each of them. One of the subjects was placed behind a wall, so that he was not visible to the others. Example configuration:

Each prisoner could now only see what was in front of him. The king told the subjects that two of them were wearing white hats and two were wearing black hats, and if one of them could shout out the color of his own hat, all four of them would be set free. If any of them said something other than the color of his own hat, they would all be killed.

How do the prisoners escape?

The solution will be posted in the comments about a week from now, if someone out there doesn’t post it first. UPDATE: Solution now available in the comments.

Neat article on the various visions of where the web is/should/could be heading and whether web 2.0 has really arrived.

Every March the American Physical Society hosts a meeting for condensed matter physics. It is a huge event— this year there are close to 6,000 physicists here. You learn about the goings on in the physics world in rapid-fire 10 minute talks. You might not think that you could learn much in a 10 minute talk, but most groups that are presenting new results have multiple group members giving talks. So after seeing 3-4 talks from the same group, you do feel like you have learned something. Anyway, I’m off to another session soon, so more later…

Email is not designed for sending big files. Most email services put a 10 MB cap on email sizes, but if you are sending an email over 1 MB, you should consider alternative ways to send your files. I guy like me will upload the file via FTP to an external server and provide you with a link, but there is now an easier way. DropSend is a service which automates this process for you. I tried it out and it really could not be simpler.