This is a little golfier.

#!/usr/bin/perl -l

$a=shift;place($a-6,0,(1..$a));sub place{local$_;$_[0]||return print @
+_[2..$#_];$_[$_] ne'#'&&place($_[0]-1,$_-2,@_[2..$_-1],'#',@_[$_+1..$
+#_])for($_[1]+2..$#_)}
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