266 out of remco's code:
Code:

Function s($d)
Dim $a,$b,$c,$,$e,$f,$g
$=" "
For $b=1 to $d
$=W+$+B
$a=$a+$d+2
Next
Redim $s[$a]
$d=2

For $c=0 to $a
$s[$c]=$
$=Join(Split($),SubStr($,$b-1,1))
$=Left($,$b-2)+" "+Substr($,$b)
$b=$b+$d
$e=2*($a/2>$c+1)-1
If 1/$d
$d=-2*$e*$d
Else
If $f
$f=$f-1
Else
$d=$d*$e/2
$g=$g+$e
$f=$g
EndFunction