http://codegolf.stackexchange.com/questions/55593/zigzagify-a-string

zigzagify.py

#!/usr/bin/env python

from numpy import *

#r = raw_input()
r = 'Programming Puzzles & Code Golf'
s = sign(diff(map(ord, r[0] + r)))
c = cumsum(s)
p = 2 * (max(c) - c) + 1
w = max(p) + 1

lr = [l        .rjust(i).ljust(w) for i, l in zip(p,   r)]
sr = ['-/\\'[j].rjust(i).ljust(w) for i, j in zip(p+s, s)]

rv = ravel(vstack([sr, lr]).T)[1:]
m = array([''.join(list(row)) for row in rv]).T
m = array(map(''.join, map(list, rv))).T


ar = array([list(row) for pair in zip(sr, lr) for row in pair][1:]).T
for row in ar:
    print ''.join(row)