Sid Shady is in prison and is planning his escape. The cell he is in measures three meters by three meters, by three meters. The walls are made of reinforced concrete and they extend two meters into the dirt floor. The only openings in the cell are a locked door and a skylight one meter in diameter. Sid thinks he has found to escape so he begins by digging a tunnel. He knows that he can't tunnel out, but digging a tunnel is crucial for his plan. How does he plan to escape?