Bolaris Grey belongs to the twisty puzzle category and that is really not my strenght. However, I decided to go for it since it was not rated as too difficult (3/10 at Mr. Puzzle Brian Young) and I could buy it at Puzzle Shop in Germany for Euro 15.-. The Bolaris ball was created by Hannu Herpje from Finland and it is already delivered in the solved state.
The idea of the puzzle itself is similar to the "15 puzzle" where you have an empty field and you need to arrange a certain state. Of course the ball has no plane surface and the smaller corner fields are fixed and do not rotate. Once scrambled you need to have the single white field on the top of the ball followed by a smaller ring of 4 light grey fields, then a big ring with normal grey fields and the last smaller ring with dark grey fields, leaving an empty field at the bottom of the ball.
This puzzle is really not that difficult and even I could solve it in about 10 minutes time. However, there are 3 more variations of this puzzle available with increasing difficulty level. There is a Bolaris Colour, a Bolaris Domino and the hardest nut is a Bolaris Earth. I really recommend beginners like me the Bolaris Grey or Colour but if you are into puzzles for quite a long time you should directly go and buy a Bolaris Domino or Earth.