main=interact$unlines.foldr(#)[[]]
f 0=""
f n=("/\\ "!!fromEnum(mod n 3)):f(div n 3)
g[]=[]
g s=g(drop 3 s)++[take 3 s]
c#s=map(" "++)s!g(f$0xca3cb1c81a820a3249a83b4937beaccbf5f`div`19683^read[c]`mod`3^9)
s!(c:t)=init s++zipWith max(last s)(c++" "):t
Note that non-ascii characters in the above source code will be escaped (such as \x9f).