There are some nice puzzles there. There is some overlap between my favourite puzzle page, by Rustan Leino: http://research.microsoft.com/en-us/um/people/leino

There are some nice puzzles there. There is some overlap between my favourite puzzle page, by Rustan Leino: http://research.microsoft.com/en-us/um/people/leino/puzzles.html http://research.microsoft.com/en-us/um/people/leino/puzzles...., but both have a number of puzzles the other doesn't. Edit: corrected Leino's name.