Is there a way to know the difficulty of a puzzle before solving it?

Yes, there is. The approximate difficulty of a puzzle is indicated by the number of stars that accompany it. The easiest problems have 1 star, the most difficult have 5. What these mean to you is difficult to say beforehand, given the differences in experience and talent among the different visitors

Why can't I see the puzzles on my computer?

You need to have the Java plugin installed in your browser. This plugin has been developed for a variety of browsers, such as Internet Explorer, Firefox, Opera, Safari and many others. The Java plugin can be downloaded from or from Sun. If it still somehow doesn't work, please report this to us at

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