main=putStr$f 0 1
s=repeat ' '
f i b|i<64=q++zipWith g p r++"\n" where
 p=t(b-i)'\\'
 r=t i '/'
 t j c=take j s++(take(128-j)$cycle$c:take b s)
 g ' ' y=y
 g x ' '=x
 q|i*2+2>b=f(i+1)(b*2+1)|0<1=f(i+1)b
f i b=[]