```#A loop is possible whenever there are two of the same lettter an even distance
#greater than 2 from each other
def first_loop(letters)
0.upto(letters.length-1) do |idx1|
(idx1+4).step(letters.length-1,2) do |idx2|
return [idx1,idx2] if letters[idx1].casecmp(letters[idx2])==0
end
end
nil
end

letters = ARGV.first.split(//)

first,last = first_loop(letters)

if first==nil
puts "No loop"
exit
end

letters[(last+1)..-1].reverse_each {|l| puts ' '*first + l}
puts letters[0..(first+1)].join
1.upto((last-first-1)/2) do |n|
puts ' '*first + letters[last-n] + letters[first+1+n]
end

----- Original Message ----
From: Ruby Quiz <james / grayproductions.net>
To: ruby-talk ML <ruby-talk / ruby-lang.org>
Sent: Friday, December 7, 2007 2:45:02 PM
Subject: [QUIZ] Word Loop (#149)

The three rules of Ruby Quiz:

1.  Please do not post any solutions or spoiler discussion for this
quiz until
48 hours have passed from the time on this message.

2.  Support Ruby Quiz by submitting ideas as often as you can:

http://www.rubyquiz.com/

3.  Enjoy!

Suggestion:  A [QUIZ] in the subject of emails about the problem helps
everyone
message,
if you can.

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

Here's a fun little challenge from the Educational Computing
Organization of
Ontario.

Given a single word as input try to find a repeated letter inside of it
such
that you can loop the text around and reuse that letter.  For example:

\$ ruby word_loop.rb Mississippi
i
p
p
Mis
ss
si

or:

\$ ruby word_loop.rb Markham
Ma
ar
hk

or:

\$ ruby word_loop.rb yummy
yu
mm

If a loop cannot be made, your code can just print an error message:

\$ ruby word_loop.rb Dana
No loop.

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```