The logician and puzzle-maker Raymond Smullyan died yesterday at the age of 97. After reports circulating on twitter, the news was confirmed, and articles in memorium have begun to appear.
Smullyan was a brilliant designer of puzzles, and his books, especially The Riddle of Scheherezade, had a big impact on me. His idea of coercive logic, in particular, impressed me deeply: with the right construction, and the stipulation that someone will answer you truthfully (or even, truly or falsely), you can compel them to do whatever you want.
The New York Times published this obituary today, which is worth the read.
The Times also published a small sampling of Smullyan’s puzzles here. It’s interactive, and a nice place to start remembering the contributions of a prolific and wonderful puzzle designer.