The History of Icons at GUIdebook, with ilustrations of the most traditional and funny icons for almost every operative system: from Lisa to Mac OS X and also Windows, NeXT, OS/2, BeOS and Linux.
There are at least sixteen of them: codes and ciphers that just resisted all cryptoanalisis over time. All of them are listed in Famous Unsolved Codes and Ciphers waiting for somebody to solve them. Some are quite well know, like the Voynich Manuscript. The list also includes the pending RSA challenges, altough some of the not-so-strong versions have been solved in the past years.
