This puzzle corner contains a few of difficult, partially unsolved yet, puzzle tasks. People who solve some ones have the possibility to send me their answer by e-mail, do not forget to include your postal address. People who send me the first, right answer are going to win a price of your choice: a sweet speciality from Brugg (Brugg's old town cobble stones) or a speciality from Schaffhausen (Schaffhausen's tongues). For delayed sendings there's still the possibility to break the predecessor's record. The right answers will be published here.
The weighting master problem with the twelve spheres
Converting of a square into an equilateral triangle
Banana transport through the desert by camel