Possible precedence problem on bitwise & operator at pdl-gameoflife.pl line 24, <DATA> line 207.
Possible precedence problem on bitwise | operator at pdl-gameoflife.pl line 25, <DATA> line 207.

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return ( ($tmp == 4) & ($pdl == 1) ) |    # Alive +3 neighbors
     ( $tmp == 3);    #  Alive +2 neighbors or dead +3 neighbors