Russian soldiers obey orders

    A line of Russian soldiers stands in front of a huge rectangular hole in the ground. Sergeant commands:

    - Private Ivanov !

    - Yes, sir !

    - Stand like this:

      O

     _|______

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    - Yes, sir !

    - Jump !

     The soldier jumps into the hole. The sergeant commands again:

     - Private Pyetrov !

    - Yes, sir !

    - Stand like this:

    | 

    | O

    \_|_

      | |

      \ \

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       | | 

    - Yes, sir !

    - Jump !

    The soldier jumps and falls into the hole. The sergeant commands again:

    - Private Sidorov !

    - Yes, sir !

    - Stand like this:

     O

    _|_

    | | |

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      |

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   - Yes, sir !

    At this point, a car with a colonel arrives to that place. Colonel, very angry, comes up to the sergeant and tells him:

    -  Comrad sergeant, how many times do I have to tell you: stop playng tetris with the soldiers !