A sudoku generator.
% rake benchmark:all
user system total real
boring (1000x): 39.090000 0.000000 39.090000 ( 39.124782)
average rating: 0.4
user system total real
easy (1000x): 48.010000 0.010000 48.020000 ( 48.072421)
average rating: 1.58
user system total real
medium (500x): 49.330000 0.010000 49.340000 ( 49.375186)
average rating: 2.57
user system total real
hard (200x): 55.390000 0.110000 55.500000 ( 55.564095)
average rating: 3.26
user system total real
insane (100x): 103.950000 0.040000 103.990000 (104.145333)
average rating: 6.07