It looks like you are trying to initialize a matrix, but do not have the syntax correct. Try

#!/usr/bin/perl -w

$a = [
   [' ',' ',' ','#','#','#',' ',' ',' '],
   [' ',' ','#','#',' ','#','#',' ',' '],
   [' ','#','#',' ',' ',' ','#','#',' '],
   ['#','#',' ',' ',' ',' ',' ','#','#'],
   ['#','#','#','#','#','#','#','#','#'],
   ['#','#',' ',' ',' ',' ',' ','#','#'],
   ['#','#',' ',' ',' ',' ',' ','#','#']
     ];
print "$a->[4][0]\n";
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This sets $a to an anonymous array of arrays - the braces you used are for hashes, and dimensioning is not needed.