Another little Crystal challenge here, this time in the form of circles and radial lines. The idea is to rotate the sets of numbers in each of the four circles, so that each of the totals in the four radial lines adds up to 9. Use cursors up and down to turn the rings anticlockwise and clockwise, and use the left and right cursor keys to select which ring of numbers you want to move. Watch out, this is tougher than you think.