Stealing the decorations part from japhy I come in at 93 chars

sub tree {
#        1         2         3         4         5         6
#23456789012345678901234567890123456789012345678901234567890
($h,$f)=@_;for$i(0..$h-1){print map($_<$h-$i?$":rand>$f?'=':

#        7         8         9
#23456789012345678901234567890123
qw(0 @ * +)[rand 4],1..$h+$i),$/}
}
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-Blake