You don't need the join. Just use the fact that print takes a list.

print$"x$h--,"*\n",map{$"x$h--,(map{rand>$f?'=':qw(* 0 @ +)[rand 4]}0.
+.2*$_),$/}1..$h
[download]

85 chars (without assignment). :-)

At some point, I'd like someone to explain to me how that nested map doesn't get confused. *laughs*

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.