Just repeat yourself Write a program that outputs 

Do not repeat yourself!


Your program code must respect the following constraints :


its length must be an even number
each character that is in position 2n (where n is an integer > 0) must be equal to the character in position 2n-1. The second character of the program is equal to the first, the fourth is equal to the third, etc.


Newlines count as characters!

This is code-golf, so the shortest code wins!

Examples

HHeellllooWWoorrlldd is a valid program

123 or AAABBB or HHeello are incorrect

Verification

You can use this CJam script to verify that your source code is valid. Simply paste your code into the "Input" box and run the script.
Hexagony, 166 126 124 bytes

\\;;;;33rr''22DD..));;;;;;oo;;}}eeoo\\@@nn;;;;ee;;;;aass&amp;&amp;;;uuoo;;;;..\\\\;;ttee..pp;;tt;;;;..rr;;''ll..'';;;;..;;}}ff..}}yy


Inserting the implicit no-ops and whitespace, this corresponds to the following source code:

       \ \ ; ; ; ; 3
      3 r r ' ' 2 2 D
     D . . ) ) ; ; ; ;
    ; ; o o ; ; } } e e
   o o \ \ @ @ n n ; ; ;
  ; e e ; ; ; ; a a s s &amp;
 &amp; ; ; u u o o ; ; ; ; . .
  \ \ \ \ ; ; t t e e . .
   p p ; ; t t ; ; ; ; .
    . r r ; ; ' ' l l .
     . ' ' ; ; ; ; . .
      ; ; } } f f . .
       } } y y . . .


I'm sure it's possible to shorten this even more, and maybe even solve it in side-length 6, but it's getting tricky...

How it works



Diagram generated with Timwi's Hexagony Colorer.

The code is completely linear. The \ right at the start redirects the IP into a diagonal, such that we don't need to worry about the doubled characters at all. The coloured paths are executed in the order orange/red, blue/grey, green, purple (when there are two paths of the same colour, the left-hand path is executed first, before wrapping around to the right-hand one).

If we ignore no-ops, mirrors and commands which are overridden by others, the linear code comes down to this:

D;o;&amp;32;}n;o;t;';}r;e;p;e;a;t;';}y;o;u;r;s;e;l;f;');@


Letters in Hexagony just set the current memory edge's value to the letter's character code. ; prints the current memory edge as a character. We use &amp; to reset the memory edge to 0 and print a space with 32;. } moves to a different edge, so that we can remember the 32 for further spaces. The rest of the code just prints letters on the new edge, and occasionally moves back and forth with ';} to print a space. At the end we move to the space edge again with ', increment the value to 33 with ) and print the exclamation mark. @ terminates the program.