Secret Codes #7

In Secret Codes #6 you solved a Caesar cipher -- you did manage to solve it, right? That cipher shifted each letter of a message to another letter in the alphabet a fixed number of positions away. So it's one form of SUBSTITUTION cipher.

The enciphered message here doesn't change letters into other letters, but scrambles the message in a particular way. It's a TRANSPOSITION cipher. Welcome to rail fence cryptography!

Rail fence ciphers are used to write a message in a zigzag form, then the letters are ordered linearly from left to right across each line. What you need to know is how many HORIZONTAL lines there are as the key. Here's an example of how to encipher a message with a key of 4. The arrow shows the direction to write the message.