The girl and the cruel king 

A cruel king was put in jail a girl who refused to marry her. After a year without the girl reverse its decision , the king brought in the castle courtyard and offers him a deal . I'll pick up two stones , one black and one white, he said, and keep them hidden in each hand. Then you will choose freely either of the two . If you pull the white stone you will be free ; if you pull the black , you'll marry me . The girl accepts this market with great fear . But his fear turns into panic when she sees that the king is looking to pick up two black pebbles surreptitiously !

What can she do to not marry the king so cruel ? 

Answers : 

This problem cited by E. de Bono ' Lateral thinking illustrates an erroneous construction of the research universe that makes the statement does indeed apparently no good solution. In reality, the constraint "I'll pick up a white stone and a black " constraint is not respected by the king, beautifully turned against him. The girl chooses a rock in one hand and the fact voluntarily immediately fall to the ground among the other in the courtyard. We see no more.

" FORGIVENESS she said , but the color of it remains , as well decide my fate , giving in contrast color the fallen ."
The other is black, of course, and the girl is FREE as it is supposed to have chosen a white fell to the ground !