Working on a 'chessboard' type of script. As you can guess, this is a row/column matrix. Below is the code and subsequent errors:

my @chessboard;
   my @back  = qw(R N B Q K B N R);
   foreach (0..7) {
      $chessboard[0][$_] = "W" . $back[$_};  # White Back Row
      $chessboard[1][$_] = "WP";             # White Pawns
      $chessboard[6][$_] = "BP";             # Black Pawns
      $chessboard[7][$_] = "B" . $back[$_];  # Black Back Row
   }

   while (1) {
      # Print board
      foreach my $i (reverse (0..7))  { # Row
         foreach my $j (0..7)  {        # Column
            if (defined $chessboard[$i][$j])  {
               print $chessboard[$i]$j];
            } elseif ( ($i % 2) == ($j %2) ) {
                  print "..";
            } else {
                  print "  ";
            }
          print " ";  # End of cell
      }  # end of foreach
    print "\n";  # End of row

   print "\nStarting square [x,y]:  ";
   my $move = <>;
   last unless ($move =~ /^\s([1-8]),([1-8)/);
   my  $startx = $1-1;  my $starty = $2-1;

   unless  (defined $chessboard[$starty][$startx]) {
      print "There's nothing on that square!\n";
      next;
   }
   print "\nEnding square [x,y]: ";
   $move = <>;
   last unless  ($move =~ /([1-8]},([1-8])/);
   my $endx = $1-1; my $endy = $2-1;

   #  Put starting square on ending square
   $chessboard[$endy][$endx] = $chessboard[$starty][$startx];
   #  remove from old square
   undef $chessboard[$starty][$startx];
   }
"my" variable @chessboard masks earlier declaration in same scope at .
+/BP_Chap11_Exer1.pl line 29.
"my" variable $i masks earlier declaration in same statement at ./BP_C
+hap11_Exer1.pl line 29.
"my" variable $j masks earlier declaration in same statement at ./BP_C
+hap11_Exer1.pl line 29.
"my" variable @chessboard masks earlier declaration in same statement 
+at ./BP_Chap11_Exer1.pl line 30.
"my" variable $i masks earlier declaration in same statement at ./BP_C
+hap11_Exer1.pl line 30.
Scalar found where operator expected at ./BP_Chap11_Exer1.pl line 30, 
+near "]$j"
        (Missing operator before $j?)
elseif should be elsif at ./BP_Chap11_Exer1.pl line 31.
syntax error at ./BP_Chap11_Exer1.pl line 19, near "$_}"
syntax error at ./BP_Chap11_Exer1.pl line 23, near "}"
Global symbol "$j" requires explicit package name at ./BP_Chap11_Exer1
+.pl line 30.
Global symbol "$i" requires explicit package name at ./BP_Chap11_Exer1
+.pl line 31.
Global symbol "$j" requires explicit package name at ./BP_Chap11_Exer1
+.pl line 31.
Unmatched [ in regex; marked by <-- HERE in m/^\s([1-8]),([ <-- HERE 1
+-8)/ at ./BP_Chap11_Exer1.pl line 42.
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TIA The Catfish