# GeekDad Puzzle Of The Week Solution: Outta Town On A Rail

Puzzle:

As I was waiting in the long, snaking security line at the airport this morning, I noticed a strange TSA code on my boarding pass. I’d never noticed it before and, given the recent changes, I began to sweat a little. What did it mean? Was I exempted from the cavity search? Would my enhanced pat-down be preceded by dinner and a movie? Would my TSA screener be gentle? Fortunately, I had hours and hours to think about what this code meant.

I was still staring at the boarding pass when I placed my shoes and laptop on the conveyor belt. But just as Rufus smiled and snapped on a new pair of rubber gloves, I got it and smiled. Can you figure out what the TSA code on my boarding pass means?

Solution:

As suggested in the puzzle headline, this is a rail or rail fence cipher. Rail fence ciphers are constructed by writing the plaintext up and down, on diagonal slopes, on a set of rails. Because the code was broken into triplets, we know that this cipher uses three rails. So we can solve the puzzle by constructing our rails like this:

If you then read the letters up and down the rails, you get the following saying that came out of the Twitter #newTSA slogans funfest last week:

It’s not a grope, it’s a freedom pat.

The “X” is added at the end to make the total number of characters divisible by three, since it was a three rail cipher.

No one came up with the correct answer, so there’s no winner this week. But you can still win by scoring a discount on some holiday presents at ThinkGeek. Just enter the code GEEKDAD29YT at check out to save \$10 on any purchase of \$40 or more.

Thanks to everyone who entered and be sure to check back on Monday when Dave Giancaspro will hopefully be awakening from his turkey coma in time to bring you another puzzle that’s sure to mash your potatoes and squash your pumpkin pies.